Multiple Admin improvements

Can now use markdown syntax in notes (bug 971584)
  Rename Note.html field to Note.note
  Backwards compatible with html markup
  Use AdminPagedownWidget for live previews in admin
Use AdminDateWidget for Release.release_date (bug 948726)
Add searching, sorting (bug 948723)
Add ESR Channel to fix bug 968258
Merge pull request #18 from jgmize/esr-channel-bug-968258

Add ESR Channel to fix bug 968258
Merge pull request #17 from jgmize/markdown-notes-bug-971584

Multiple admin improvements
Use settings.RNA['VERIFY_SSL_CERT'] in client

Allow temporary workaround for bug 973499
Also useful for local dev against unsigned cert
Sort notes by tag for bug 974695
Merge pull request #20 from jgmize/sort-notes-by-tag

Sort notes by tag for bug 974695
Merge pull request #19 from jgmize/ssl-error-workaround

Allow disabling ssl cert verification in setting as temporary workaround for bug 973499
Reset migrations to fix bug 963805

If running against an existing DB with all previous migrations
applied, you will want to run the following after merging this:

./manage.py migrate rna 0001 --fake --delete-ghost-migrations
Merge pull request #21 from jgmize/reset-migrations

Reset migrations to fix bug 963805
Add Language and Feature tags to fix bug 979050
Merge pull request #22 from jgmize/language-feature-tags

Add Language and Feature tags to fix bug 979050
Add helper methods to Release for bug 965012

Release.equivalent_android_release() for use on desktop releases
Release.equivalent_desktop_release() for use on android releases
Ensure (product, version) unique-- fix bug 980151

Add utils to deduplicate product versions
Add schema migration for unique constraint
Merge pull request #23 from jgmize/unique-together-product-release

Ensure (product, version) unique-- fix bug 980151
Fix sorting now that some versions have only 1 dot
Merge pull request #25 from mozilla/equivalent-release

Add helper methods to Release for bug 965012
Make Release.notes return lists for bug 985839

Make it easy to check if there are no known issues
from the template
Add Release.get_bug_search_url for bug 983366

Also add major_version method used in get_bug_search_url
Merge pull request #27 from jgmize/default-bug-search

Add Release.get_bug_search_url for bug 983366