Bake 0.2.0

Enhancements

• Users can set default_target globally
• Added bake help. In addition to displaying option menus when the command is invalid, a user can ask for more information about a module, bake help system will show more informations like systems
• Added ability to clean all systems and toolchains by passing --all to bake system clean --all and bake toolchain clean --all
• Consolidated BakeUtils and BakeDaemon into Bake.

Bug Fixes

• Nerves adapter checks return status of environment source and will exit on error.
• Support for 0.6.0 toolchains