First implementation of QTI conversor
Multiple response (one choice only is the correct one) QTI converter implemented
Multiple choice and multiple response quizzes
True-false QTI export added. MC y MR questions now working fine
Shuffle parameter set to false in MC MR
Export to QTI functionality finished
git ignore modified
New image added
Merge branch 'master' of https://github.com/ging/vish into qti

Conflicts:
	vendor/plugins/vish_editor/app/assets/javascripts/vishEditor.js
	vendor/plugins/vish_editor/app/assets/javascripts/vishEditor.min.js
	vendor/plugins/vish_editor/app/assets/javascripts/vishViewer.min.js
	vendor/plugins/vish_editor/app/scorm/javascripts/vishViewer.min.js
Minor changes
Identation and bugs fixed for IMS QTI 2.1
Some refactoring for IMS QTI 2.1 exporting
Delete QTI tmp files