Disable spell checking and substitutions

OS X’s text substitutions aren’t helpful when dealing with code. Spell
checking is rarely useful in these cases either.
Use a fixed-width font for the insert data text view
Merge pull request #122 from abitgone/master

Disable text replacements, automatic spell checking and switch to a fixed-width font for the Insert Data view
update README
Merge branch 'master' into new-mongo-c-driver

Conflicts:
	Sources/ConnectionWindow/MHQueryWindowController.m