convert GUI to use ttk for more native look and feel

Ttk widgets are the easiest way to get a more native look and feel with the
widgets.  It does also work on Mac OS X, but its not included until Python
2.7, which was not included in Mac OS X until 10.7.

refs #1967
refs #1968
add app icons to installer and set path to load them from

refs #1967
refs #1968
keysync-gui: convert input sources to new app icon style

This is the first step in implementing the v0.2 GUI sketched here:
https://guardianproject.mybalsamiq.com/projects/gpgcleanroom/KeySync%20-%20preliminary%20ChatSecure-only%20sync

This also leads towards the v0.3 GUI.

refs #1967, #1968
split out QR Code window into its own method, for readability

refs #1967, #1968
keysync-gui: play QRCode window directly over main KeySync window

This makes the next step obvious and prevents the QRCode window from
getting lost on a big screen, or a screen with lots of open windows.

refs #1967, #1968
disable widgets on mainscreen when the QRCode window is displayed

This puts all the focus on the QRCode window as the only action to do once
the conversion has been run.  Closing the QRCode window re-enables all of
the widgets.

refs #1967, #1968
gajim: read in and parse public keys and verified status

Gajim's *.fpr is the same tab-separated format as libotr's
add standard app field: '.files' for a list of all relevant files for that app

This makes it easy to check if a given folder belongs to a specific app.
For example, if the folder contains all three files in the
AdiumProperties.files list, then that folder is for Adium.

refs #1967
refs #1968
keysync-gui: preload all app icons, both enabled and disabled

This makes it easy to show the app icon wherever it makes sense

refs #1967, #1968
keysync-gui: create window for manually choosing the path to an app's files

refs #1967, #1968
chatsecure: always encrypt otr_keystore, even if it has no secret key data

Its easier to have a single standard file format, plus its good to protect
metadata and social graph information.

refs #1876
add key bindings for closing windows

refs #1967, #1968
keysync-gui: include per-platform paths for location of icon files

refs #1967, #1968
clean up layout and colors for Mac OS X

refs #1870, #1967, #1968
update Mac OS X build instructions

refs #1870
automatically set manually added app type based on detecting conf files

refs #1967, #1968
use items() for looping thru keydicts for Python 3.x support and efficiency

Python 2.x's iteritems() is probably only more efficient than items() if
the loop breaks when it finds something.  items() makes the whole dict into
a list, while iteritems() only works on the parts of the dict that are
actually accessed.

http://stackoverflow.com/questions/10458437/python-what-is-the-difference-between-dict-items-and-dict-iteritems
add bonjour data to test cases for pidgin and Adium (still need more)
keysync-gui: if device MTP is detected, show simple sync UI

This is currently only implemented using GNOME gvfs, since it just mounts
MTP devices on the filesystem, so its very easy to detect and handle.

refs #1967, #1968