added mptt and python field
default raw string for url component
h1ds_mdsplus no longer used. mds code now in h1ds_core.backends
remove mdsplus from available module list
h1ds data module no longer a separate app
Merge branch 'drf'

Conflicts:
	requirements.txt
rename doc to docs
add abridged requirements file for readthedocs
Merge pull request #3 from dpretty/master

Merge django-rest-framework branch