Added height 16, alignment, more control over code output, vastly improved png, plus some bug repairs

[hb020]

• added height 16 (was missing in the range 8,24,32,40,48,.. ). I just needed 16.
• print_ascii now also makes the .h file more "debuggable"
• added the printable character in comment to the .h output
• corrected a bug that if font_height was set, it would break
• added "lowerascii" standard set: space + signs + punctuation + digits
• raised the version from 2.1 to 2.2
• adapted readme to reflect the additions

[hb020]

• Added better width control
• Added vertical anchor control (nice for baseline or bottom alignment)
• Greatly improved the generated png: it now matches the header files, with respect to clipping and alignment.
• Repaired some bugs that arose mainly on variable width symbol fonts (negative widths for example) and protection against non standard file formats.
• Bumped version to v2.3

[hb020]

And repaired some small bugs.

[hb020]

made it compatible with Tiny4kOLED's style of font definitions (and probably others), be it for fixed width or for variable width fonts.