Merge pull request #1 from wsnipex/upgrade-pr

Allow automatic xbmc upgrades on linux
don't say you need to upgrade if you have a pre version installed
move json functions to it's own file
remove obsolete includes
declaring a variable one time is enough
move version compare to seperate file
just pass throught the string id and localize at the end
remove unneeded includes
move linux specific imports and only when needed
remove unneeded
update changelog
add some temporary logging
show the yes/no dialog on linux when using the fallback method instead of the ok dialog
increase version
fix error on local variable 'handler' referenced before assigment.
use common function for yes/no dialog
[linux] fix shellhandler when no package is installed
bump version