Further SD API cleanup.

Making file and fileOpenMode private.  Removing old functions.

libraries/SD/SD.cpp

@@ -327,8 +327,7 @@ void SDClass::begin(uint8_t csPin) {
 }
 
 
-File SDClass::open(char *filepath,
+File SDClass::open(char *filepath, boolean write, boolean append) {
-			       boolean write, boolean append) {
   /*
 
      Open the supplied file path for reading or writing.

libraries/SD/SD.h

@@ -12,8 +12,8 @@
 
  */
 
-#ifndef __MEMORY_CARD_DEVICE_H__
+#ifndef __SD_H__
-#define __MEMORY_CARD_DEVICE_H__
+#define __SD_H__
 
 #include <WProgram.h>
 
@@ -43,37 +43,34 @@ class SDClass {
   
   
  public:
-  // This needs to be called to set up the connection to the memory card
+  // This needs to be called to set up the connection to the SD card
   // before other methods are used.
   void begin(uint8_t csPin = SD_CARD_CHIP_SELECT_PIN);
   
   // Open the specified file/directory with the supplied mode (e.g. read or
-  // write, etc). Once opened the file can be accessed via the
+  // write, etc). Returns a File object for interacting with the file.
-  // `MemoryCard.file` field which is a standard `sdfatlib` file object.
+  // Note that currently only one file can be open at a time.
   File open(char *filename, boolean write = false, boolean append = true);
 
-  // Close an opened file object.
-  //boolean close();
-
   // Methods to determine if the requested file path exists.
   boolean exists(char *filepath);
-  //boolean exists(char *filepath, SdFile& parentDir);
 
   // Create the requested directory heirarchy--if intermediate directories
   // do not exist they will be created.
   boolean makeDir(char *filepath);
 
-  // At the moment this is how a developer interacts with a file they've
+ private:
-  // opened. It's unclear whether it would be better to make
+  SdFile file;
-  // `MemoryCard` provide a `Stream` interface instead.
-  SdFile file; // TODO: Don't make this public?
 
   // 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; // TODO: Don't make this public?
+  int fileOpenMode;
+  
+  friend class File;
+  friend boolean callback_openPath(SdFile&, char *, boolean, void *); 
 };
 
 extern SDClass SD;