Merge pull request #6 from tosik/master

Changes to create a gem foundation, command-line system and some features.
Fixes TODO in gemspec
Fixes a fetch command bug.

It can't fetch the same version SDK as fetched version.
Merge pull request #11 from tosik/gemify

Fixes TODO in gemspec
Merge pull request #12 from tosik/fixes/same-package-fetch

Fixes a fetch command bug.