Start fixing speedmeter
Some fixes
Fix position of speedmeter

Only need to get the texture
Tweak checkbox position on login screen
Don't let irrlicht process tab events. FIxes #1619, fixes #1225, fixed #1454
Manually keep track of the duration each sfx has been played (instead
of relying on the world clock, which can run backwards, e.g. in
FTL mode). Fixes #1624.
Merge branch 'master' of github.com:supertuxkart/stk-code
Fixed typo in warning message.
Properly test for sfx disabled, and only schedule events if sfx
are enabled. Fixes #1629.
Fix texture