1159067 - Read user cred from config

Allow pulp to read user credentials from users admin.conf
if he/she does not want to provide password on command prompt
or --password in pulp-admin
add doc of permissions argument to role update
1021579 - document unexpected behavior in unassociate api
PEP-8 test_content_sources.py.
Add a flake8.cfg.
PEP-8 the content sources model tests.
Merge branch '1066022' into 2.4-release
Merge branch '2.4-testing' into 2.5-testing
Merge branch '2.5-testing' into 2.6-dev
Updates for 2.5.1 becoming 2.6.0
Merge pull request #1337 from CUXIDUMDUM/cuxidumdum/1159067

1159067 - Read user cred from config
Updates to docs to describe bug process
Merge pull request #1338 from beav/bugprocess

Updates to docs to describe bug process
I hit "merge" before pushing an updated commit with feedback from #1338.

This commit has some minor updates to the PR.
Merge pull request #1340 from beav/bugprocess

I hit "merge" before pushing an updated commit with feedback from #1338.
Merge pull request #1336 from bmbouter/update-for-2-6-release-stream

Updates for 2.5.1 becoming 2.6.0
remove unnecessary return
make 100 characters a hard limit in docs
Merge pull request #1332 from asmacdo/docs-line-limit

make 100 characters a hard limit in docs
Removes master.rst and moves feature note to 2.6 release notes