Bw-temporalis

* Fix [15](https://github.com/brightway-lca/bw_temporalis/issues/15) - Switch `temporal_distribution` to have `amount` sum to one
* Fixes for [bw_graph_tools](https://github.com/brightway-lca/bw_graph_tools) version 0.2.2
* Lowered default cutoff values in graph traversal

* New convolution implementation improves speed and removes dependency on `bw2speedups`
* Fix [1](https://github.com/brightway-lca/bw_temporalis/issues/1) - Add utility function to check if temporal distributions sum to amount values
* Fix [6](https://github.com/brightway-lca/bw_temporalis/issues/6) - Better error message for to_dataframe when timeline is empty
* Fix [8](https://github.com/brightway-lca/bw_temporalis/issues/8) - Add clustering for to reduce complexity of large `TemporalDistributions` after convolution
* Fix [9](https://github.com/brightway-lca/bw_temporalis/issues/9) - Add utility function to generate temporal distributions
* Fix [12](https://github.com/brightway-lca/bw_temporalis/issues/12) - Add utility function to visualize temporal distributions

* Can pass custom `graph_traversal` class to `TemporalisLCA`

Bugfix release

* Change exchange label from `temporal distribution` to `temporal_distribution`
* Add climate change characterization methods
* Add `supplement_dataframe` utility function

Initial release

Added

Changed

Removed