revised type URIs, artifactId + slightly improved code on client-side.

Improvements:
- extracted eduzen rest client into emc.js
- reduced doublings in code, especially URIs (not complete yet)
- cleaned up imports in java classes
- assigned custom types manually to default workspace (because of non-standard "dm4.*" uri)
- localized math-rendering
- added robustness if content of note is empty
- fixed client-side app-model cache (through localizing cache updates)

Administrative:
- deactivated tracking

Pending:
- allow users to manipulate the tag-filter per item
- enable users to edit and delete tags in single-resource/detail view
- consolidate timestamps on application level

Administrative:
- depends on the latest commit in the dm4.reviews-plugin

Note: You must reset your DB.

Testing continues.