Temporarily remove link in README.md to Windows installer (until PATH is fixed)

Right now, some users are finding that the 0.6.22 Windows installer overwrites their PATH variable.  We will link back up to the installer when we are sure that it is fixed.
Improve README.
Merge pull request #157 from virtual-world-framework/branch/remove-installer-from-readme

Temporarily remove link in README.md to Windows installer (until PATH is...