Turn g:SZAK_BIGGER_FONT from a boolean into an actual size.

I should've known when I first set this up, but on a couple of boxes I
really want a different size.  Having this be a value works out much
better.
Tweak the coloring for listchars to be a little less noticeable.

I don't want it distracting me from the code, but I want to know that
it's there too.  This seems like a good balance.
Merge branch 'allow-disabling-powerline' into mine
Merge branch 'replace-enhancedcommentify-with-tcomment' into mine

Conflicts:
	doc/notes.txt
	doc/tags