Merge pull request #342 from modilabs/client-performance

correct XSLT sheet versioning check in transformation caching mechanism
Merge pull request #343 from modilabs/client-performance

missing part of last caching-fix
Merge pull request #344 from modilabs/client-performance

final correction to XSLT caching mechanism
created static drishti folder with html template and assets, created custom js build for drishti, upgraded bootstrap to 2.3.0
spelling correction
removed unused images
Merge pull request #345 from modilabs/drishti_static

Drishti static
formtester validation fixed, closes #348
drop IE8 support, closes #346
recompiled
Merge branch 'master' of https://github.com/modilabs/enketo into client-performance

Conflicts:
	Code_Igniter/application/controllers/formtester.php
	src/scss/styles.scss