RC2 Update 1

* Added automatic updating option - will check whenever Spriggan is
started.
* Changed the AddonTable tag filter to use a vertical ScrollPane. SO
MANY TAGS.
* Added more files to DEFAULT_INSTALL_IGNORE
* Implemented a tool to export simple Addon JSON. Useless to most
people.
* Implemented a context menu item for the Repository which allows users
to change the remote Readme location of Addons, if adding an addon
manually which doesn't conform to its standards.
* Created a TextInputPopupBase class
* Changed NewAddonPopup and NewMasterlistPopup to inherit this
*