block types

block types:

__Tasks:__

- [x] test coverage
- [x] gather feedback for my changes
- [x] submit changes to the documentation
- [x] xml schema
- [x] cache class rendering
- [x] blockproperty type changes
- [x] block content type
- [x] contentmapper
- [x] ui in contentbundle (https://github.com/sulu-cmf/SuluContentBundle/pull/131)

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | no => https://github.com/sulu-cmf/SuluTestBundle/pull/11
| Fixed tickets | none
| Doc           | https://github.com/sulu-cmf/docs/blob/master/detail-specification/300-webspaces/DET-301-template-architecture.md