Merge pull request #88 from artificialio/addon-system

Implemented SANE's addon system.

Fixed wrong variable name.

Version bump 0.0.21.

Forgot a superspawn require.

Fixed windows commands and bumped version.

Merged together branches and bumped version.

Updated changelog and manual merge.

Fixed some bugs and version bump.

Some bug fixes and bump version.

Minor fix with port-forwarding and added verbose flag for up command.