Change instructions for enabling access for assistive devices for 10.9 (and have it open the right part of prefs using scripting). Switch to 10.9 SDK.

Make unblockPipeW nonblocking (pun not intended) to fix bug 2633. The PTYTask thread would get stuck in readTask waiting for the mainThread to complete -[PTYSession readTask:] while the main thread was stuck in -unblock waiting to write to unblockPipeW, which is only read by the PTYTask thread. Since unblockPipeW was blocking, it must have had a lot of pending writes that hadn't been read off, and dropping one on the floor won't matter because the thread will definitely get unblocked.

Fix crasher where a CRun attribute's color could get dealloced when another NSColor was created with the same attributes. Not sure why autorelease semantics are violated this way by NSColor. The fix is to explicitly keep a reference to every color used in a run in the CRunStorage object.

When changing an existing session's profile, also change its idea of what its original profile (originalAddressBookEntry) was so that when splitting it splits with the new profile instead of the old one. Fixes bug 2632.

Fix double-free of colors in CRun's because they were being treated as weak refs by CRun and strong refs by PTYTextView.m

Use CGFontGetGlyphAdvances instead of sizeWithAttributes in FontSizeEstimator.m to deal with change in later SDKs

Resolve merge conflicts from cherry-pick of d148ad8b (Fix memory corruption bug. Realloc'ed codes, glyphs, and advances in CRunStorage were not having their pointers updated in CRun)

fix bug where arrange horizontally computed the wrapping position incorrecly if the screen's visible frame wasn't 0