installation: fix for MathJax OS X install issue

* MathJax library was copied with cp -ur, however the -u option is not
  supported on OS X.  (closes #1455)

Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebAccess: fix variable parsing in robot auth

* Fixes an issue where a variable was wrongly assumed to always contain
  a string even though it could also contain integers.  (closes #1456)

Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>