* main.cpp: removed path checking and db loading
 * card database: merge card loading methods into a single one
 * settings cache: take care of returning safe paths for decks,
replays, etc..
 * main window: if db loading fails (eg. first run), propose to run
oracle

NSIS: propose to run cockatrice instead of oracle

Rework card database loading

 * Move carddatabase-related method out of deckeditor tab
 * Load cards in another thread and render them progressively
 * Optimize database reload after enabled sets change

Fix deck editor column width

 * removed the noCard hack.
 * getCard() no more creates cards instead of just returning existing
ones
 * Fix the “edit tokens” dialog.
 * PictureLoader: avoid trying to download twice the same card
 * PictureLoader: correct return of card background
 * AbstractCardItem: avoid recalculating card color at every paint

Use a different file to save custom tokens

Misc required improvements

 * Use nullptr;
 * Refactor CardInfoWidget to use CardInfoPicture and CardInfoText
instead of duplicating code;
 * Added CardInfo::getColorChar()
 * Fixed some potential crashes
 * removed dead code related to CardInfoWidget
 * Don't require a restart after adding a new custom sets file
 * Bump CMake requirements to 3.1

Fix #340

After feedback, and also noticing myself, the blue requires a little
more focus than should be nessesarry. I have updated to be orange, which
feels more comfortable. I have polled the community and they also agree
orange > blue.

I compare the card pt, to the card with the same name in the db. if the
card is found, we compare the pt, of the db item and the item in play.
If there is not a match then we change the color of the PT. This is
pretty much the same as mtgo does it.

I looked into having only the P, or the T colored, though this is not
posible, when you set a pen color you can not change it partway through
painting a string. That would require 3 strings painted, one for p, /
and t. Which is more effort than its worth. This does the job pretty
well.

I have also moved the pt slightly to the left so it lines up better. I
have some images to compate.

+ Updated DELTA variable to more suitable name:
ROTATION_DEGREES_PER_FRAME

+ Cards now animate smoother and faster
+ removed redundant computations performed each frame

Click-holding on a card then immediately releasing now properly changes the
cursor from a closed hand back to an open hand

if cards in multiple zones are selected, don't create drag items for the ones you're not supposed to move

Revealing a library to a player now grants that player permission to drag cards out of that library onto his own table. This permission is revoked by shuffling the library. The zone view window tracks content changes of the zone for as long as the permission lasts so that card ID changes are kept track of. This hopefully fixes issues #5 and #12.

stop card tap/untap animation in CardItem::resetState() to avoid unfinished animation during zone change