TxiInstall and TxiUninstall should be abstract
Load F0F
JLoader::import() housekeeping
Update minimum PHP version check and set it to PHP 5.3.3
Improve minimum Joomla versions check
+ Database table installation, uninstallation and updating is now handled by F0F instead of the unreliable JInstaller code
First load the latest F0F version at the (un)installation script

See: https://github.com/akeeba/release-system/pull/44