Fixed some linting errors and made the merge_streams() code cleaner as well as added more unit testing

Cleaned up merge_stream(), takes empty channels out at the beginning and adds them in before the merge() function

Reset the Timeseries Utility to the master. The changes will be introduced in a separate pull request

Fixed npts issues in create missing and channels as well as a unit test. Also cleaned up the unit test code for syntax and linting.

Fixed logic in XYZ test under unneccessary channels

Added unit tests to XYZAlgorithm_test.py for limited channels as well as gaps in unneccesary channels

Cleaned up channel initialization in XYZalgorithm and calls to get_required_channels() in algorithm.py

Added channel options to can_produce_data and get_stream_gaps so get_required_channels can be used for XYZAlgorithm functionality

Intermagnet fixes

Changes to fix missing channel specification issues in XYZAlgorithm and StreamConverter, added a get_required_channels option

Merge branch 'python3-url-support' of https://github.com/jmfee-usgs/geomag-algorithms into jmfee-usgs-python3-url-support