Merge pull request #18 from sachith500/bug1056

addons_screen minor fix
Fix failed override attempt
Misc code improvements
Don't use raw char*, use std::string instead. Fixes leaks.
Rewrite bizarre code in a way that makes more sense
Fixed bug #1056 Addons search last updated option text is cropped

changed addons_screen.stkgui to ensure the filterdate spinner had adequate space.

Signed-off-by: Sachith Hasaranga Seneviratne <sachith500@gmail.com>