Basic support for esp8266 platform

This includes empty stubs for most core Arduino functions.
Need to actually implement all those digital reads writes whatever.
Need to prebuild toolchains (xtensa-elf-lx106) for 3 platforms and put them on some download server.
Need to do the same with esptool.
Need to fix 0x40000 binary generation and add correct upload commands.
Maybe even implement uploads over WiFi.

cores/esp8266/Stream.h

@@ -0,0 +1,102 @@
+/*
+  Stream.h - base class for character-based streams.
+  Copyright (c) 2010 David A. Mellis.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+  parsing functions based on TextFinder library by Michael Margolis
+*/
+
+#ifndef Stream_h
+#define Stream_h
+
+#include <inttypes.h>
+#include "Print.h"
+
+// compatability macros for testing
+/*
+#define   getInt()            parseInt()
+#define   getInt(skipChar)    parseInt(skipchar)
+#define   getFloat()          parseFloat()
+#define   getFloat(skipChar)  parseFloat(skipChar)
+#define   getString( pre_string, post_string, buffer, length)
+readBytesBetween( pre_string, terminator, buffer, length)
+*/
+
+class Stream : public Print
+{
+  protected:
+    unsigned long _timeout;      // number of milliseconds to wait for the next char before aborting timed read
+    unsigned long _startMillis;  // used for timeout measurement
+    int timedRead();    // private method to read stream with timeout
+    int timedPeek();    // private method to peek stream with timeout
+    int peekNextDigit(); // returns the next numeric digit in the stream or -1 if timeout
+
+  public:
+    virtual int available() = 0;
+    virtual int read() = 0;
+    virtual int peek() = 0;
+    virtual void flush() = 0;
+
+    Stream() {_timeout=1000;}
+
+// parsing methods
+
+  void setTimeout(unsigned long timeout);  // sets maximum milliseconds to wait for stream data, default is 1 second
+
+  bool find(char *target);   // reads data from the stream until the target string is found
+  bool find(uint8_t *target) { return find ((char *)target); }
+  // returns true if target string is found, false if timed out (see setTimeout)
+
+  bool find(char *target, size_t length);   // reads data from the stream until the target string of given length is found
+  bool find(uint8_t *target, size_t length) { return find ((char *)target, length); }
+  // returns true if target string is found, false if timed out
+
+  bool findUntil(char *target, char *terminator);   // as find but search ends if the terminator string is found
+  bool findUntil(uint8_t *target, char *terminator) { return findUntil((char *)target, terminator); }
+
+  bool findUntil(char *target, size_t targetLen, char *terminate, size_t termLen);   // as above but search ends if the terminate string is found
+  bool findUntil(uint8_t *target, size_t targetLen, char *terminate, size_t termLen) {return findUntil((char *)target, targetLen, terminate, termLen); }
+
+
+  long parseInt(); // returns the first valid (long) integer value from the current position.
+  // initial characters that are not digits (or the minus sign) are skipped
+  // integer is terminated by the first character that is not a digit.
+
+  float parseFloat();               // float version of parseInt
+
+  size_t readBytes( char *buffer, size_t length); // read chars from stream into buffer
+  size_t readBytes( uint8_t *buffer, size_t length) { return readBytes((char *)buffer, length); }
+  // terminates if length characters have been read or timeout (see setTimeout)
+  // returns the number of characters placed in the buffer (0 means no valid data found)
+
+  size_t readBytesUntil( char terminator, char *buffer, size_t length); // as readBytes with terminator character
+  size_t readBytesUntil( char terminator, uint8_t *buffer, size_t length) { return readBytesUntil(terminator, (char *)buffer, length); }
+  // terminates if length characters have been read, timeout, or if the terminator character  detected
+  // returns the number of characters placed in the buffer (0 means no valid data found)
+
+  // Arduino String functions to be added here
+  String readString();
+  String readStringUntil(char terminator);
+
+  protected:
+  long parseInt(char skipChar); // as above but the given skipChar is ignored
+  // as above but the given skipChar is ignored
+  // this allows format characters (typically commas) in values to be ignored
+
+  float parseFloat(char skipChar);  // as above but the given skipChar is ignored
+};
+
+#endif