Moved InvalidPackage from ipkg.utils to ipkg.exceptions
Only use packages matching the environment platform
Made Requirement objects testable with ==
Updated PackageRepository API
New module: ipkg.platforms

It replaces ipkg.platform and adds platform matching
Added make_filename
made PackageFile accept meta on instantiation, allow for delaying real file opening
bugfix: use the already computed json value
tests for IpkgException
manage platform requirement
Make the package path public
Use make_filename
Fixed build tests
Rewrote ipkg.repositories