Descarteslabs

Fixes
- Automatic retry on 504
- Internal API refactoring / improvements for Auth

Added
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* Add raster bands methods to metadata service.
* Deprecate raster band methods.
* Add require_bands param to derived bands search method.

Fixes
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* Test suite replaces original token when finished running script tests.

Added
- Support for derived bands endpoints.
- Direct access to `const_id` to `product` translation.

Fixes
- `descarteslabs` scripts on windows OS.

Fixes
- Fix auth login

Added
- Add metadata.bands and metadata.products search/get capabilities.
- Add bands/products descriptions
- Additional Placetypes

Fixes
- Better error messages with timeouts
- Update to latest version of `requests`