Wagon

* Add support for excluding specific packages via the --exclude (-x) flag which can be supplied multiple times. This will be reflected in the metadata.
* Add wagon showmeta -s SOURCE_ARCHIVE which prints out the metadata of a wagon archive.
* OS properties in the metadata are now null when all either creating an archive on OS X or Windows or if the platform is any.
* Archive name now contains the distro and release if creating an archive on Linux which contains non-Pure-Python wheels; but, when irrelevant, archive name will be somewhat like this: cloudify_fabric_plugin-1.2.1-py27-none-any-none-none.tar.gz

* Added support for user supplied Python versions.
* Added support for an --ignore-platform flag when installing a module.
* Archive name now includes distro and release for Linux compiled archives so that they're identifiable.
* Much more documentation

* Rename Wheelr to Wagon
* Add creation and installation validation.