Major refactoring of resourceloader. This version loads graphical resources when...

Major refactoring of resourceloader. This version loads graphical resources when they are first required, instead of loading them all when the game starts. Resources are cached using SoftReference<> and reclaimed by the Android OS whenever needed.
Refactored resourceloader of conversationcollection. Now the game only loads conversations when they are used in the ConversationActivity, instead of loading them all when the game starts.
These two changes drastically reduces the memory footprint of the game, thus allowing devices with lower maximum heap size to run the game.

Changed link to forums (http://andorstrail.com/)

git-svn-id: https://andors-trail.googlecode.com/svn/trunk@181 08aca716-68be-ccc6-4d58-36f5abd142ac