Optimize pictures with optipng.
Optimize svgs with scour.
Add shellscript for optimization.
Improve IE Compatibility

Added meta tags from HTML5 Boiler Plate to improve compatibility with IE7+. This fixes the issues with rendering.
The "lost password" field depends on OC_USER_BACKEND_SET_PASSWORD

so it should only be visible for users with a supporting backend.
[tx-robot] updated from transifex
fix for losing private key while being logged in and accessing a public link
fix for undefined index
Merge pull request #3512 from owncloud/file_encryption_session_fix

fix for losing private key while being logged in and accessing a public link
Merge pull request #3488 from zafi/master

The "lost password" field in the personal setting depends on OC_USER_BACKEND_SET_PASSWORD
Merge pull request #2778 from Kondou-ger/optimize_pictures

Optimize pictures with optipng.
Merge pull request #3179 from pawl/patch-1

Improve IE Compatibility
merge master into sessionclass