feat(editorView): zoom camera on screen center
refactor(fontawesome): use fontawesome source for LESS
feat(paneItem): directive for grouped sections in left pane

- Add suppport for specifying fontawesome icons in CSS rather than forcing inclusion in html.
- Hide feature under the surface, to move on to better things.
feat(documentView): directive for viewing documents of any type

- Acts as factory for correct view based on document type as determined by its metadata.
- Currently supports Images, Tiled Maps, and text based documents for a fallback.
refactor(documentView): convention for document types

- Use convention typeEditorView.* for editor directives, and place them in directives/editors.
- Convert existing editors to convention.