Add application object for storing configuration information

This is only the first use of the `app` object. Asset loading, i18n,
gamesaves, and scene management are all planning on going through the
app object.
single use is now true
Merge pull request #1024 from CalebJohn/chicken-leg

Chicken legs single use
Merge pull request #1023 from hawkthorne/globalapp

Add application object for storing configuration information