Correct Cython dependency
Debian or Ubuntu
Clean up installation instructions

 - Don't even **tell** users how to install with `sudo pip install`
   or `sudo python setup.py install`. Improper use of `sudo` seems to be
   the number one cause of broken Python systems.
 - Document MacPorts, Debian, and Ubuntu packages
Correct Utopic URL
State minimum pip version
Add upgrade instructions
Oops, change transition phrase after rearrangement of paragraphs
Make README.rst install instructions identical to INSTALL.rst

Also, make them appear more prominently, earlier in the document, and
provide a hyperlink to INSTALL.rst.
Remove redundant and almost empty section
Re-wrap paragraphs to 80 columns
Use full project URL, not just Github user URL
Merge pull request #174 from lpsinger/install_instructions_cleanup

Install instructions cleanup: README.rst and INSTALL.rst