vim: more conservative synchronization heuristic

Hopefully less buggy!
vim: remove Counter from python code, no longer rely on python2.7+
configure: Use tput instead of hardcoded color constants
vim: python compat, fix wrong synchronization condition
vim completion: include quote in characters valid for identifiers
complete: handle completion of "."
vim: Return completions compatible with vim < 7.3
vim: Fix format string syntax for compat with py < 2.7

Conflicts:
	vim/autoload/merlin.py
Merge branch 'experimental'

Conflicts:
	vim/autoload/merlin.py
vim-mode: Tweak type printing heuristic
Apply relevant modifications from type-error branch.
Merging heuristics from different branches...
Fixed merging of vim modes from experimental and type-error.
emacs: Append merlin-ac-source to ac-sources instead of replacing it.

Closes #19.