#7 Add documentation for firmware commands

[Pascal]

I noticed that the firmware seems to support "undocumented" commands. At least they are not documented here http://openprog.altervista.org/OP_eng.html.
The corresponding defines are right before void Read18FKx(int dim,int dim2,int options)

#define LOAD_PC_ADDR 0x80
#define BULK_ERASE 0x18
#define ROW_ERASE_PROGRAM_MEM 0xF0
#define LOAD_NVM 0x00
#define LOAD_NVM_INC 0x02
#define READ_NVM 0xFC
#define READ_NVM_INC 0xFE
#define INC_ADDR8 0xF8
#define BEGIN_INT_PROG 0xE0
#define BEGIN_EXT_PROG 0xC0
#define PROGRAM_DATA 0xC0
#define PROGRAM_DATA_INC 0xE0
#define END_EXT_PROG 0x82

It would be good if these would be documented somewhere so that the relevant information would be available to extend op to support additional devices.

[Alberto Maccioni]

These are not firmware commands; they are used as payload for ICSP8_LOAD and refer to PIC18 commands. A full description is available in the device programming specification.