Sets handling improvements

Double click room fix

Port #436 to QDateTime

Add 'Start time' column to game list

Don't remove card images from revealed decks

Action: Move Bottom Card to Graveyard

Double click/ENTER to join a room in lobby

Added the same functionality to the server tab

Can now join a room by highlighting a room and pressing ENTER. Works
nice with arrow navigation.

Can now double click on a room in the lobby to join

ref #452

Added fade to card drag items

[REVIEW]
Added a white mask to cards that are being dragged.

Preview: http://webmup.com/1we4W/

Cards Scale with mouse over action

QT_VERSION check now checks for correct version

Let oracle add a basic TK set in cards.xml
Unify all the code previously using the string literal “TK”

Added "order key", "set type" and "release date" columns
Use a proxy model to sort the table
made the dialog wider accordingly

Build both Qt4 and Qt5

Feature is only included in Qt 5.3+