Adding license.
Setup.py and .cfg updates.
Adding pyflex logo.
Mostly documentation work across the codebase.
Absolute and relative times for the windows class including tests.
Low level interface documentation.
Readme for the documentation.
water level and acceptance levels are now arrays.

Effectively results in the same functionality as the old user functions.
Configuration for signal and noise time ranges.
Global SNR based data quality checks implemented.
Logging SNR info.
Refactoring signal and noise time frame determination.
Per window signal to noise calculations.
Duplicate removal function now also recenters the windows.
Taking origin time into account.
Fancier plot.
Fixing dlna computation.
Changing xlabel.