1. Re-arranged html structure, used html5 features.
2. Added multiple images capability, images can be added one-by-one or
selecting them with ctrl/cmd from the file dialog.
4. Output for multiple images can be represented by a single byte array
or with a byte array for each images, its identifier will be increased
with a trailing counter.
3. Added ‘GFXfontBitmap’ support.
4. Other smaller improvement.
NOTE: still under testing.
Adds the option to change the byte array variable name, useful if a lot
of copy/paste of the generated code is required. The option becomes
visible when “Adda Arduino code” is checked.