Don't assume homebrew install location
Remove instructions about homebrew Python path

Homebrew no longer links Python scripts into /usr/local/share: 

    https://github.com/Homebrew/homebrew/blob/master/share/doc/homebrew/Homebrew-and-Python.md
Remove URL path from the Chrome CSP in development

For some reason this fails to inject scripts in Chrome (38.0.2125.122)
due to CSP violation even though the two paths appear to match. Removing
the path from the host/port seems to fix the issue.