Brightway2

- Changes to improve testing for bw2data and bw2calc

- Fix some places where set_current wasn't introduced
- Rework initialization of projects and add projects tests
- Moved tests to main directory

Windows tests are failing due to naughty strings being used for project names.

- Deprecated `projects.current = 'foo'` in favor or `projects.set_current('foo')`
- Added ability to switch to read only project with `projects.set_current('foo', writable=False)`
- Removed separate write of topomapping files from inventory databases. All topology handling is internal to bw2regional
- Fixed bug where `download_file` wouldn't raise an error is resource was not found.

- Fix database writes not propagating to search index
- Added continuous integration tests on Windows
- Fix bug when iterating over projects

- Better `__str__` for metadata
- Make projects sortable
- Allow forcing writes with `projects.enable_writes(force=True)`

- Bugfix release to add unstated dependency of `pyprind`