Added Edit > Paste Special > Paste with Literal Tabs

Also fixed "Paste Selection Escaping Special Characters" command
Updated documentation

The Toolbelt Paste History window does not correctly handle formerly paste-special'ed text

Signed-off-by: Brian Doyle <brian@balance-software.com>
Updated Paste with Literal Tabs to support large amounts of pasted data.

Previous commit only handled pasting a small amount of data, when the paste
code went into the slow paste callback cycle the don't-discard-control-codes
state was lost.  In this commit the state is passed along via the PasteContext.
Improve advanced prefs image
Fix bugs with escape code file downloads
Connect to SSH agent.
Don't call interpretKeyEvents: directly from -sendEvent: when there is an IME open. I don't know why we did that before, but it caused bug 2882. Instead, just let the event go through the normal channels (bypassing special key handling in -sendEvent:, though).
Various changes per gnachman's suggestions

- removed code added to PasteContext
- moved control code stripping to pasteString:flags:
- changed tabs to spaces
- removed spaces after : in methods (e.g. arg:foo)
comment syn -> lnext
formatting
Update PTYSession.m
formatting
formatting
Merge branch 'master' of https://github.com/gnachman/iTerm2
Retain images loaded in initialize method of PTYTextView
Unblock TaskNotifier when SIGCHLD is handled.
Merge branch 'master' of https://github.com/gnachman/iTerm2
Add some debug logging to the dvr code
Merge branch 'master' of https://github.com/bdpdx/iTerm2 into bdpdx-master
Get rid of incredibly outdated stringReplaceSubstringFrom:to: method in favor of stringByReplacingOccurrencesOfString:withString:
Clean up pasting.