update angularjs to 1.2.19 and remove superfluous angular-sanitize
set routes for settings tabs:
- introduce angular-route module
- refactoring: 'settings' refers to page, 'options' to first tab
- tab retrieval via templateUrl, has its own nonce
- fix: transformRequest not as default but only for ajaxFactory actions
move description editor from dialogue to page
customSelectElement: on emission of 'select' event publish an identifier
as additional argument
new Feature: difficulty levels for crosswords:
- restrict allowed directions for words
- show or hide word list in solve mode before the words are found
- changes crossword schema
- includes a small fix for customSelectElement
- includes fix in serverside debug message construction