Fixing a bug caused by YAML::load(Pathname).

The fix is to call Pathname#read and pass the contents of the file to
YAML::load. Passing the pathname itself caused a strange infinite loop
that consumed all available memory and processor, which I haven't been
able to reproduce except with that classpath cache file.
Merge pull request #79 from rdblue/master

Fixing a bug caused by YAML::load(Pathname).