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
Update Zend_Mime to latest version
Merge pull request #1714 from mlocati/update-zend_mime-1.12.5

Update Zend_Mime to latest version
Don't show Download button for Multi-Site
Fix build-release grunt task

Occasionally the build-release grunt task fails with the error
"... has no method 'endsWith'"
Using the latest version of the download npm module fixes this.
Merge pull request #1724 from mlocati/fix-grunt-build-task

Fix build-release grunt task
Merge pull request #1722 from worldskills/fix-update-multi-site

Don't show download button for Multi-Site