Collada Export: escape user-defined strings in XML output.
Merge pull request #344 from assimp/collada_export_escape

Collada Export: escape user-defined strings in XML output.
Collada : Add missing parsing <image> into <effect><profile> markup
Merge pull request #347 from vloppin/master

Collada : Add missing parsing <image> into <effect><profile> markup
Merge remote-tracking branch 'upstream/master'