Place the trojita icon in the right directory

The trojita icon is 64x64 but was being placed in
/usr/share/icons/48x48/* directory. resolved to store in
/usr/share/icons/64x64/*

BUG: 332640
REVIEW: 117115
Fixed build error
Adding proper credits for Niklas
tests: check parsing of "numbers" where string is expected
scroll the message w/ keyboard on mbox focus
autoscroll when reaching viewport upper/lower edge
Fix relative executable path and wrong icon path in desktop file

Changed Exec=./trojita to Exec=trojita

Changed icon path to 64x64 directory

BUG: 332642
REVIEW: 117119
Installed into system locations, trojita can't be started

This fixes not looking in standard data locations for the installed qml
files. To fix this it first checks if main.qml exists in the current
source tree, if not then we get a list of standard data locations and
try to find main.qml and throw qFatal if can't be found.

BUG: 332639
REVIEW: 117109

Conflicts:
	src/Ubuntu/main.cpp
Move ThreadingMsgListModel to ImapAccess

REVIEW: 117127
merge scroll-by-keyboard branches
distance dependent autoscrolling
Ubuntu version: Use tab to switch TextFields in ImapSettings.qml

REVIEW: 117183
Adding icons for Ubuntu

These are copied or derived from the ubuntu-mobile-icons package available a
http://packages.ubuntu.com/raring/all/ubuntu-mobile-icons/download
and are available under the CC-BY-SA 3.0.
Copyright by 2004-2012, Canonical Ltd.

REVIEW: 117192
Fix missing path in Ubuntu/main.cpp

BUG: 332639
REVIEW: 117202
Ubuntu: fix insecure access to CWD when looking up files

The logic wa sapparently to make sure that we can find the QML file when run
straight from the build dir. However, it is important to use the path to the
aplication binary instead of the $CWD because otherwise Trojita would do
extremely dumb thing when called from inside an attacker-controlled directory.

This commit also adds the path to the app's exec file to the list of paths to
perform the lookup in order to preserve the desired functionality.
Ubuntu: clean up the path manipulation a bit

There's no need to clutter the original variable.

Also use QFile::exists as per Thomas' recommendation.
Ubuntu: do not mess with appDir path when using user-provided location

This enables stuff like `trojita --qml /path/to/it`.
Ubuntu: remove support for passing paths to QML files

There's no need to do this. The app will always load the QML from a path
relative to the application's own location (which handles the case for running
from inside the build directory). If that is not available, systemwide locations
are consulted as a fallback.

I just don't see any use case behind having to pass paths here.
Ubuntu: Remove debugging output
Ubuntu: It's Trojitá, not Trojita, and add l10n