v0.4.0

Biggest Change

• Add SGP4 prop and offer C API / python bindings into it
  • This implementation is the fastest open source option for SGP4 orbit prop

What's Changed

• PD-51: LSK kernel parsing by @ATTron in #35
• PD-16: fix file readers by @ATTron in #36
• fix tcp timing bugs introduced by @ATTron in #38
• fix issues with new Io package by @ATTron in #40
• clean up some formatting by @ATTron in #39
• io changes by @ATTron in #41
• bump zignal to fix breaking FITS tests by @ATTron in #42
• make things a little less choatic by @ATTron in #43
• clean up imports by @ATTron in #44
• spg4 prop by @ATTron in #45
• refactor how orbit prop is designed by @ATTron in #46
• maneuver updates by @ATTron in #47
• C API + Python Bindings by @ATTron in #48
• package python bindings Part 1 by @ATTron in #49
• spg4 with python and benchmarks by @ATTron in #50

Full Changelog: v0.3.0...v0.4.0