fixup `rake build_server` task

Nightly CI was failing against the master toolchain because the dylibs step was failing.

I grouped the 'build' and 'install' phases together instead of building all the libraries and then installing all the libraries.

The build_server task was pretty crufty, so I spruced things up a bit and updated the documentation.

5ecd21d is a big whitespace change so the final diff is hard to read.