Release 0.12.17

ANDROID: remove hardcoded references to /sdcard path

SDL: fix ALT key handling

Tagged for release

WEB: fix compile error

Tag for release 0.12.8

UI: updated help

Merge pull request smallbasic#45 from chrisws/0_11_20

0 12 6

Merge pull request smallbasic#22 from chrisws/0_11_17b

COMMON: cleanup datatype, save image, screenshot menu