add sources controller.
use serializer.
add get single content source.
add unit tests.
add binding tests.
add rest docs.
Fix failing nodes test.
add test.
Add permission decorator.
Merge pull request #1231 from pulp/jortel-us3033

Content sources API for listing sources.
1153054 - pulp.bindings refuse to do SSLv3.

This commit configured pulp.bindings.server to refuse to do SSLv2 or SSLv3.
TLSv1.0 and greater are allowed.

https://bugzilla.redhat.com/show_bug.cgi?id=1153054
Merge branch 'disable_sslv3' into 2.4-testing
Merge branch '2.4-testing' into 2.4-dev
Merge branch '2.4-dev' into 2.5-testing

Conflicts:
	bindings/pulp/bindings/server.py
Merge branch '2.5-testing' into 2.5-dev
Merge branch '2.5-dev'