update tablesorter from 2.0.5b to 2.18.3
Merge remote-tracking branch 'upstream/master' into tablesorterUpdate

Conflicts:
	src/uLearn.Web/Scripts/_references.js
* check update tablesorter in Quiz Analytics
* small sorting fixes
fix white-spaces and comments in table-configurator.js
remove default-value and deprecated options in table-configurator.js
Merge remote-tracking branch 'upstream/master' into tablesorterUpdate

Conflicts:
	src/uLearn.Web/Scripts/_references.js
Merge pull request #10 from Tinkturianec/tablesorterUpdate

Tablesorter update