Rename Ston-Core.package and Ston-Tests.package directories  to STON-Core.package and STON-Tests.package 

Sven,

This pull request brings the directory names in alignment with the new package names ... the following show up as additions/deletions, but they are benign:

- [.travis.yml file](https://github.com/dalehenrich/ston/compare/dir_rename?expand=1#diff-354f30a63fb0907d4ad57269548329e3R1) which is useful for automated testing 
- [STONReader>>lookupClass:](https://github.com/dalehenrich/ston/compare/dir_rename?expand=1#diff-10c1e4a7f08439e1e9fd5cf88c1f9063R1) which is a formatting difference because of an earlier cherry-picking error
- [STONReader>>lookupClass:](https://github.com/dalehenrich/ston/compare/dir_rename?expand=1#diff-45c64199ef6d38594e4b95df5294299aL1) which is the cherry-picking error ...

If you want, I can delete the `.travis.yml` file from the pull request and I can restore your original formatting for STONReader>>lookupClass: