1.0.0 - first stable release

[wolearyc]

This version will mark the first stable release. This will be the last chance to make API changes (before v2, of course).

Goals

• Code stability through a greater variety of tests
• Documentation polish
• Exception handling
• Better imports in tests - it is OK to have a mixture of import types. whatever's most readable...
• Automatic file format recognition in generic IO
• file_format should be case-insensitive
• Code comments where appropriate
• check for properties
• str (or repr) methods for all classes
• Trajectory appending and manipulation
• Black formatting in jupyter notebooks 3b4145c