Important changes:
* Refactored QtRequests to accept parameters for `GET` operations
* Infer response data type from content-type header
* Support caching to disk, a manager with this set prefers the cache
* Support multiple handlers for a single request (unused, possibly pointeless)
* Subclass `ShopImageWidget` for all widgets used in the shop
* Request a resized image instead of the original one
* Fix the search and browse functions
QToolButton is not really designed to be used in the way we did and since
QPushButton supports having a menu attached to, we can replace tool buttons
in most cases.
* Fix the presentation of the TabButtonWidget by updating RareStyle's css
* Reduce the size of the top tab bar to save vertical space.
* Remove infoLabel property
