Merge pull request #1 from jinxcat/master

TLE handling
Merge pull request #2 from jinxcat/master

skeleton of tracker
Merge pull request #3 from jinxcat/master

object creation/removal in tracker
First take on SDR sub-project
Add simplesdr system dependencies
Merge pull request #5 from jinxcat/master

tracking and example of usage
Merge pull request #4 from comzeradd/master

First take on SDR sub-project
Merge pull request #6 from jinxcat/master

bugfix on tracking
slight changes to constants