* 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

 * Removed remaining picture handling from card database and cardinfo
 * removed the “noCard object” hack

Moved setting files & Added code for a future portable build

cardframe is now a stacked widget that prefers to show the card picture
only so that the screen can be more space efficient and the card pixel
map can be displayed as a larger size. however if the card pixel map
can not be loaded for some reason, the cardframe class will automatically
switch to the text version of the card.

a menu item was added under the database menu to allow for users to
prefer card text only.

the original layout is actually more space efficient if using CardFrame
instead of CardInfoWidget and reducing the size of the deck editor
toolbar.

this commit also removes the old search feature by removing the search
button and the clear search button. the clear search menu item is left
in place, however it now clears the filtertree.

finally, the stretch factor for the right frame in the main layout was
reduced to zero so that the card database gets priority for extra space.
this makes more sense because the deck editor does not actually need
very much horizontal space.