[WIP] Responsive Curve2

This PR gives SMF 2.1 to handle some resolutions to display properly (aka Responsive). Admin side currently untouched and probably stay that way for now.

**Note to testers (this message will be deleted after some changes), after lots of merge-conflicts i restarted working on this and left some old changes for now, I'll bring them back**

##### Test area;
- Soon (there is already a site with some of those changes but I'll create dedicated one with latest changes, since other site is not up-to-date you can face already fixed issues and i don't want to waste your time).

##### Tested with:
- Nokia Lumia 520
- Samsung Galaxy S3
- Samsung Galaxy Note2
- Nexus7

Fixes #272
Fixes #347
Signed-off-by: Antes <antes@simplemachines.org>