Update install script

Update osxdefaults file location to bin directory as that is the correct
location for binaries; it's not related to any of the binaries, and
should be accessed from the $PATH when it gets sourced.

Issue: #9
Update install script

Update the location of install script to /sbin as opposed to /bin. This
is a major update and the following are the reasons:

- Initially I was using @necolas dotfiles installation; however he
  doesn't source his /bin directory in his $PATH for whatever reason; I
  want my /bin files in my $PATH so they are accessible from anywhere in
  bash as well as autocompletable.
- When the install script sources the `.bash_profile` it causes an
  infinite loop of installation as that is where the install file is
  located
- After doing some research into filesystem naming conventions, I ran
  across an [article][1] that pointed to, what I feel is, a more
  appropriate location, /sbin, which is for "essential system binaries".
  Given that the installation is essential to this entire thing, I found
  it appropriate and a solution to the current problem.

[1]: http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

Issue: #9
Update install script

- Delete open sans cask font installation as it was removed
- Delete python installation from brew packages; its installed when
  installing pip
- Update quicklooks cask install to be verbose when creating the folder
  (debugging)
- Update pip package installations to check for current homebrew'd
  version of python before upgrading

Issue: #9