Move the “check unknown sets” method inside the cards database, so that
it can be executed when the card database gets reloaded after a card
database update.
Additionally, show the user a welcome message the first time they run a
new cockatrice version, so that they know why they get shown the “edit
sets” window and how to hide/disable sets.

Needs to be tested on mac

Please note that I don't feel that the search bar needs to be skinned by
users, hence why it is not part of the large css-skinning project. I
also feel that given the PR #416 a new search bar with highlight the new
search functionality.

Updated the look of the search  bar:
+ larger, curved edges
+ changes color when has focus
+ search icon built into search
- removed "Search For" text in lieu of search icon

Ref #112

removed LEFT/RIGHT increment/decrement while
the card database/quicksearch edit have focus.
LEFT/RIGHT increment/decrement remains while the
deck view has focus.

also, now the card database delegates focus the
quicksearch editor so that any characters typed
while the card database has focus will narrow
the search down using the quicksearch filter.

`control`+`alt`+`-`/`=` now increment/decrement
the mainboard and `control`+`alt`+`[`/`]` now
increment/decrement the sideboard (alt could not
be used alone as OSX inserts special characters
using alt.

The global shortcuts were removed in favor of key events
which are only triggered when a widget has focus. This is
necessary to allow different widgets to react differently
to the 'enter' key. The current key configuration is:
search edit focused:
  * left/right: decrease/increase card count for selected database card
  * enter: add selected card to deck
  * ctrl-enter: add selected card to deck sideboard
  * ctrl-left/right: decrease/increase card count in sideboard for selected card

database focused: the same as with search edit.

deckview focused:
  * left/right: decrease/increase card count for selected deckview card
  * enter: increase count for selected deckview card
  * delete/backspace: delete selected card from deck

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.

renamed filter list modules to filter tree to more accurately reflect
the nature of the data structure.

filter builder takes filter options from user, then adds
completed filters to the filter tree. the filter tree does
not currently do anything. in the future it will filter the
cards in the database view.

deck editor is tab, replay viewer is tab, deck editor shown by default, cache window geometry between sessions, 'open this deck in deck editor' open in game