emacs: add whole-line-or-region

When the region is not active perform some commands on the whole current
line. Do this for kill-region, kill-ring-save, and comment-dwim.
emacs: enable whitespace-mode in vala-mode
emacs: remove android-mode

was having an issue with it after upgrade, and I don't use it anyway.
emacs: use ido for ggtags completing read

makes C-u M-. really useful - jump to a tag in the project using ido to
select the tag.