Don't free null run
Fix bug where the char under the cursor wasn't drawn
Fix bug where cursor blinked while moving
Merge branch 'v2' of https://github.com/gnachman/iTerm2 into v2
Resolve merge conflicts from cherry-pick of d148ad8be9cb3cf5ebbb8f3783b17ebf2a6d0e50 (Fix memory corruption bug. Realloc'ed codes, glyphs, and advances in CRunStorage were not having their pointers updated in CRun)
Use default compiler and SDK for developement builds
Fix warnings
Fix underlines
Resolve merge
resolve merge conflicts
Fix merge problems