Re-arrangement of documentation for the v0.6.0 release.
Moved the feature interface documentation and tidied up some bad links.
Removed the introductory examples, which are now redundant.
Added the features example.
Review actions: New logo, new example (from what's new section), tidied all examples, fixed broken links.
Fixed sort order of gallery.
Merge remote branch 'origin/feature_interface_docs' into v0.6.x

* origin/feature_interface_docs:
  Fixed sort order of gallery.
  Review actions: New logo, new example (from what's new section), tidied all examples, fixed broken links.
  Added the features example.
  Removed the introductory examples, which are now redundant.
  Moved the feature interface documentation and tidied up some bad links.
  Re-arrangement of documentation for the v0.6.0 release.

Conflicts:
	lib/cartopy/__init__.py