Fix data-hidetype="undefined" appearing

* Checkboxes must be reset after defining the event handlers
* .prop doesn't seem to trigger, so use .trigger('click') instead
* I dislike initializing hideType with keys (another dependency)
Show full avatar when hovering in avatar-only mode
Remove unused CSS selectors
Replace API_KEY constant in SteamAPIClient
Refactor SteamAPIClient

* Replace lastCallSucceeded with an exception (I think I was too lazy to create a new file before)
* Prefer early returns
* Replace some unnecessary preg_replace'ments
Make SteamAPIClient more flexible in preparation for future changes

* Add forceCache parameter to the get* functions so that you can easily have different behavior between calls
* SteamAPIClient should not handle any request data
* Prefer $options in constructor so that any option can be overridden without hardcoding the values of the precedents
* `get` takes a data array for reasons similar to the above bullet
* Assume app IDs and player IDs are mutually exclusive, so remove trailing/leading underscores from cache paths
* Replace magical API_KEY definition with an "api.key" file
+player IDs
Merge pull request #25 from Southpaw018/full-avatars

Full avatars; closes #16
Merge pull request #26 from Southpaw018/api-flexibility

SteamAPIClient flexibility