v0.4.0

Release notes

Added

• Support for --build-type option for build command. The use of this option is
  documented in detail in "docs/configuration.md". --build-type option was
  tested exhaustively with unit tests and various test fixtures with pytest. The
  tests can be found in tests folder.
• Projects using east tool from now on need east.yml file in the root directory.
  See above mentioned document.

Fixed

• Error code propagation through Nordic's Toolchain Manager.