Improved clean() function in fabfile.py

- It now cleans up all of the following:
    - cmd2.egg-info directory
    - dist directory
    - docs/_build directory
    - htmlcov code coverage directory

Also:
- Tested that the fabfile works with the fabric3 "fab" command
- Removed raw Sphinx docs from MANIFEST.in and hence the PyPI tarball
    - It probably wouldn't help end users to include the raw restructured text files

Author: tleonhardt

MANIFEST.in

@@ -4,6 +4,5 @@ include CHANGELOG.md
 include CODEOWNERS
 include CONTRIBUTING.md
 include tox.ini
-recursive-include docs *
 recursive-include examples *
 recursive-include tests *

fabfile.py

@@ -21,6 +21,10 @@ def mkdirs(path):
 def clean():
     local("python setup.py clean")
     local("find . -name '*.pyc' -delete")
+    local("rm -rf cmd2.egg-info")
+    local("rm -rf dist")
+    local("rm -rf htmlcov")
+    local("rm -rf docs/_build")
 
 
 @task