[WIP] Generalizing a SpatialEvents class

[magdalenafuentes]

This PR implements #58, introducing a SpatialEvents class that inherits from Events and extends it adding spatial information such as azimuth or distance of the sound source. Notice that this is meant to be used for annotations where spatial information changes over time. Otherwise, if position of sources is static we include spatial information as metadata.

[magdalenafuentes]

Before I go further in the implementation of the tests let me know what do you think @justinsalamon @nkundiushuti @iranroman

[codecov[bot]]

Codecov Report

Merging #61 (1302bdb) into main (c8dc7a8) will decrease coverage by 1.26%. The diff coverage is 82.97%.

:exclamation: Current head 1302bdb differs from pull request most recent head 86c9f85. Consider uploading reports for the commit 86c9f85 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #61      +/-   ##
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- Coverage   98.52%   97.26%   -1.26%     
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  Files          24       18       -6     
  Lines        2096     1465     -631     
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- Hits         2065     1425     -640     
- Misses         31       40       +9