Do git and GH issue house cleaning during releases

Author: Kurt Yoder

RELEASE.md

@@ -1,6 +1,8 @@
 To release:
 * Verify pass in [CircleCI](https://circleci.com/gh/greenmoss/PyWavefront)
     * Check against latest `master`
+* Update local git
+    * `git fetch -ap && git pull origin master`
 * Update `CHANGELOG.md` from merged PRs
 * Update contributors in `README.md`
 * Update version in `setup.py`
@@ -10,3 +12,6 @@ To release:
 * `python setup.py bdist_wheel`
 * `twine upload dist/$(ls -tr dist/ | tail -1)`
 * Create Github release, named as version
+* Close Github issues associated with merged PR
+* Update local git
+    * `git fetch -ap && git pull origin master`