Added community home page. This PR closes #89.

Fix Collection Homepage Errors

remove Matrix URL notation

Support embedded resources in rest responses

Refactored community and collection pages to use a shared component for most of the content. This PR connect’s to #89

Collection home page

Shows the following fields if they exist:
* title
* logo
* introductory text
* news (also referred to as sidebarText)
* copyright text
* license

Fixes https://github.com/DSpace/dspace-angular/issues/63

Full item page

Travis build timeout: this connects to #101