Always enable localization cache

Localization cache is enabled only if the initial locale is not en_US.
But, mainly on multilingual sites, we may have an initial en_US locale,
and the final locale is set after the initialization of the Localization
library.

So, let's always enable the localization cache...
Faster autoloadCore checks

Loader::autoloadCore is called hundreds of times for each page: let's speed
it up by using case-sentivive strings comparision
(strpos is about 40% faster than stripos: see http://3v4l.org/3GC1s )
Remove some unused code
bug fix to progress history with a deleted user
Merge pull request #1700 from mlocati/improve-loader-autoloadcore

Faster autoloadCore checks
Merge branch 'fix-localization-cache' of https://github.com/mlocati/concrete5 into mlocati-fix-localization-cache
Reverting Date/Time Helper
Merge branch 'mlocati-fix-localization-cache'
Merge pull request #1702 from Mnkras/patch-7

Remove some unused code
updating version