Modified to use data binding, bugfixes, cleanup

Clean up includes:
 - Giving classes that contained only static methods the "static" keyword
 - Modifying form to use data bindings to automatically syncronize options
   as well as automatically populate the history item information
 - Changing the history removal functions to create a deep copy of the
   currently selected items to prevent loops overstepping their bounds
 - Minor refactoring
 - Added JsonIgnore attributes to parts of HistoryItem that shouldn't be
   serialized

Bugfixes include:
 - Logic bug in where registry keys were placed
 - Crash on non-JSON response from Imgur
 - Crash on deserialization of null image
 - Maybe some other stuff, it's been way too long at this point
Moved save location to appdata, minor cleanup

Moved the code in Form1_Visible to Form1_Load and changed it to fire when
the form loads, instead of every time it was shown; the code in there is
only necessary once on load. Removed lines in SelectedHistoryItemChanged
setting defaults; data binding takes care of it. Fixed minor bug causing
multiple items in the history to be selected when one is removed.
Updated dist folder