refactored bootstrap.sh

1) allow for building a local python instead of using one already on the OS
   (in case there isn't one already, or in case you want to play with newer
   versions).

2) allowed for a --prefix for installing python, and a --workdir for installing
   your virtualenv workspaces

3) added virtualenvwrapper to the default/template buildout.cfg

4) made everything a commandline parameter.  Looked at and discarded using
   argument parsers including getopts, getopt, getopt_long, and getopts_long.
   I only wanted long options and it was easiest (this pass) to write my own.

5) removed the prompt for asking for extra modules to add to buildout.cfg.
   Adding these manually is a (relatively simple) exercise for the reader.

5) tried to do some sanity checking on the parameters given.  There are still
   some nasty bugs lurking, so I may work on these more in the near future.

6) started to work on passing in proxy settings so that the bootstrap.sh
   script can control that for wget/curl.  Unfortunately I have a hostile
   proxy at work and I need some more testing to try to find the combination
   that works for all of wget, curl, and python (buildout, pip, etc).
finishing merge from origin/master