Issue #141: Introduce state system for environment-specific,  non-configuration settings.
Isuse #141: Adding caching to state system.
Issue #141: Clearing cache on state value delete.
Merge branch '1.x' into 141/state_system
Issue #141: state_set() needs to update static states variable if it already exists.
Update README.txt

The themes directory is now in root directory.
Merge pull request #126 from anacona16/patch-1

Update README to reflect location of themes.
Merge pull request #125 from quicksketch/141/state_system

Issue #141: Introduce state system for environment-specific,  non-configuration settings.