dbl-tempo-initial

Scope of enhancements

• remove required prefix from python resample logic (specify prefix for resampling) - bars calculation uses pre-set prefixing.
• update resample logic to accept interval-style strings (1 minute, 2 hours, etc) for more customization
• update scala version for changes above
• update error handling in python and scala for acceptable functions for aggregation in resample logic
• updated readme to account for changes above
• updated setup.py for pypi upload