Plac module

Added Plac module description
Updating links for brew
Merge pull request #363 from jasonh-n-austin/master

Updating links for brew
Switch from Chishop to pypiserver
update "env.rst"
add comma
Merge pull request #365 from cli248/update-envrst

update "env.rst"
Merge pull request #364 from schmichael/goodbye-chishop

Switch from Chishop to pypiserver
Merge pull request #362 from DhiaTN/patch-1

Plac module
update intro section: add Pro Python link
remote duplicate Chef in admin.rst
add link to Numba
update untangle link
update Ubuntu Python packaging docs link
expand "-" belongs to "Ansible"
Merge pull request #367 from cli248/update

Several modifications