Fix for issue #46 Error on page_password while installing

- Move session_start(); up to be the first statement
Fix for issue #50, SCORM 1.2 uses non mandatory SCORM variables

- Check whether variables are supported by LMS
- Suppress errors from the apiwrapper
- Also fixed a race condition
Merge branch 'master' of https://github.com/thexerteproject/xerteonlinetoolkits
MathJax retired old hosting address of SSL CDN and aligned it with http
address
Merge remote-tracking branch 'origin/master' into develop
Merge remote-tracking branch 'origin/develop' into editor