This is mainly a maintenance release from a user perspective. In reality it
contains a significant contribution from @dontlaugh which overhauls the
sorting/filtering mechanism and testing system.

Bugfixes

• Task addressing by ID outside context is now fixed: #44
• ZSH tab completion when expanding negative tags is fixed (zshrc update required) #35

Maintenance

Courtesy of @dontlaugh:

• More unit tests
• Improved integration tests