Remove duplicate code for copying advanced working dir prefs
Replace string literals for working directory with consts
Move labels in general profile prefs to new prefs
Reorganizer project file for new classes
Move URL scheme registration/deregistration/lookup to iTermURLSchemeController
Move url schemes popup to new prefs
Move change profile controls in general tab of Edit Current Session to new prefs
Move set profile label, visible only in Edit Current Session, to new prefs
Move color wells over to new prefs but lots of testing is needed.
Fix bindings for most controls in colors tab of profile prefs
When a shared profile changes, update PTYSession's originalProfile to match it. Don't call sharedProfileDidChange unless the shared profile did change, because that overwrites the session profile (prior to this commit, editing the session profile with View>Edit Current Session didn't work at all because I removed the equality comparison from the if statement's condition clause). This could use more testing.
Use flush instead of writing prefs to nsuserdefaults, since we want flush to be a no-op for the sessionsInstance
Move color preset menu to new prefs
Move minimum contrast to new prefs
Move labels in colors tab over to new prefs