msie version test and document mode (quirks mode)

[SebC99]

In some cases IE runs in a different document mode (mainly depending of doctype) and it can cause some errors:
Angular tests the IE version (like in angular.js line 2057: if (msie <= 8) ) but doesn't test the document.documentMode (specific to IE).

I guess we could replace the msie variable by the document.documentMode if exists because the user-agent isn't a reliable test for feature detection, whereas documentMode is a little better.

[Narretz]

Implemented in a84480a