0.4.0
 - BREAKING CHANGE: change metadata key names 
 - enh: add class for checking metadata
0.3.0
 - feat: support tab-separated values file format (*.tab)
 - fix: file formats were not registered correctly
 - ref: derive file format errors from own error classes
0.2.0
 - compatibility changes towards nanite
0.1.0
 - initial version
