client.kak: allow granular terminal ordering in termcmd option
client.kak: add termite in termcmd option
Use unsigned char rather than char in utf8 decoding to avoid sign extension
utf8: use end of sequence iterators for more security
Improve colalias documentation in README
Minor style cleanup
Add support for paste all (on <a-[pP]>)

Paste all pastes all yanked text at all selections, selecting each
pasted text.

Replace paste moves to R, and concat yank/concat delete (Y and D)
are removed.

Fixes #161
NCurses: better support for 256 color terminals that cannot change colors
More consistent <space> and <a-space> behaviour

<space> and <a-space> without count now remove all except/keep
main selection. Without reducing main selection to cursor.

Reduce to cursor is moved to ';' and flip selections to <a-;>
Document space and ';' changes in README
Merge remote-tracking branch 'alexherbo2/termite-termcmd-option'