Merge branch 'master' of https://github.com/supertuxkart/stk-code into devel
Merge pull request #1336 from supertuxkart/shader-fix

Fix shader problems when UBO is disabled.
Start refactoring materials
More material work
Add lightviz to spheremap
Add lightviz to instanced node
Merge remote-tracking branch 'origin/master' into MaterialsRefactor
Spheremap: fix low brightness
Merge remote-tracking branch 'origin/master' into MaterialsRefactor
Fixed saving login credentials. It's now possible to switch
user (and automatically a logout and login is triggered).
Merge remote-tracking branch 'origin/master' into new_login
First attempts at new RTT widget, does not work yet
Improve material compat fallback + update one handwritten materials XML
Tweak the scattering value to reduce the effect
Checked for valid email id.

Email id is checked for (z)(z)*@(z).(z)
where z is an alphanumeric character. 
Following emails are valid: abc@xyz.com a@abc.com
d@ddyC00l@abc.com foo@ab.com
Following are invalid: abc foo@ @foo.com @.com .com@
Checked for valid email id.
Spaces removed
Tested changes for wchar
Rolling back changes,no need to edit here
Use core::stringw functions