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.

libraries/SD/src/SD.h

@@ -0,0 +1,102 @@
+/*
+
+ SD - a slightly more friendly wrapper for sdfatlib
+
+ This library aims to expose a subset of SD card functionality
+ in the form of a higher level "wrapper" object.
+
+ License: GNU General Public License V3
+          (Because sdfatlib is licensed with this.)
+
+ (C) Copyright 2010 SparkFun Electronics
+
+ */
+
+#ifndef __SD_H__
+#define __SD_H__
+
+#include <Arduino.h>
+
+#include <utility/SdFat.h>
+#include <utility/SdFatUtil.h>
+
+#define FILE_READ O_READ
+#define FILE_WRITE (O_READ | O_WRITE | O_CREAT)
+
+class File : public Stream {
+ private:
+  char _name[13]; // our name
+  SdFile *_file;  // underlying file pointer
+
+public:
+  File(SdFile f, const char *name);     // wraps an underlying SdFile
+  File(void);      // 'empty' constructor
+  virtual size_t write(uint8_t);
+  virtual size_t write(const uint8_t *buf, size_t size);
+  virtual int read();
+  virtual int peek();
+  virtual int available();
+  virtual void flush();
+  int read(void *buf, uint16_t nbyte);
+  boolean seek(uint32_t pos);
+  uint32_t position();
+  uint32_t size();
+  void close();
+  operator bool();
+  char * name();
+
+  boolean isDirectory(void);
+  File openNextFile(uint8_t mode = O_RDONLY);
+  void rewindDirectory(void);
+  
+  using Print::write;
+};
+
+class SDClass {
+
+private:
+  // These are required for initialisation and use of sdfatlib
+  Sd2Card card;
+  SdVolume volume;
+  SdFile root;
+  
+  // my quick&dirty iterator, should be replaced
+  SdFile getParentDir(const char *filepath, int *indx);
+public:
+  // This needs to be called to set up the connection to the SD card
+  // before other methods are used.
+  boolean begin(uint8_t csPin = SD_CHIP_SELECT_PIN);
+  
+  // Open the specified file/directory with the supplied mode (e.g. read or
+  // write, etc). Returns a File object for interacting with the file.
+  // Note that currently only one file can be open at a time.
+  File open(const char *filename, uint8_t mode = FILE_READ);
+
+  // Methods to determine if the requested file path exists.
+  boolean exists(char *filepath);
+
+  // Create the requested directory heirarchy--if intermediate directories
+  // do not exist they will be created.
+  boolean mkdir(char *filepath);
+  
+  // Delete the file.
+  boolean remove(char *filepath);
+  
+  boolean rmdir(char *filepath);
+
+private:
+
+  // This is used to determine the mode used to open a file
+  // it's here because it's the easiest place to pass the 
+  // information through the directory walking function. But
+  // it's probably not the best place for it.
+  // It shouldn't be set directly--it is set via the parameters to `open`.
+  int fileOpenMode;
+  
+  friend class File;
+  friend boolean callback_openPath(SdFile&, char *, boolean, void *); 
+};
+
+extern SDClass SD;
+
+#endif