Merge pull request #96 from wunderio/feature/python3

Fix Python 3 compatibility issues

Merge pull request #92 from hugovk/pep8-to-pycodestyle-master

Merge pull request #95 from wunderio/feature/drush_command_error

Raise build error if drush command fails.

Merge pull request #94 from wunderio/feature/composer_working_directory

With '-d=' build script couldn't find _build directory and composer install didn't start.

Merge pull request #93 from wunderio/feature/composer_exit_code

Raise build error if composer install fails.

pep8 is now pycodestyle

Merge pull request #90 from wunderio/no-interaction

Option "--no-interaction" is added to "composer install" command on non-development environments to prevent command line prompts on deployments. Default action as to whether changes need to be discarded can be defined in composer.json file with "discard-changes" option set to "true", "false" or "stash".

Fix composer not building properly on current dir when defining target build dir.

Merge pull request #89 from wunderio/feature/composer_dev_override

Allow environments to specify if composer dev packages should be installed