v2.1.0alpha

New features:

• Single measurements (or groups) can be deselected
• Table, diagram and polefigure are now tabs in the main frame
• Improved control tabs for detector, peaks, interpolation
• Diffractograms can be saved into multiple, numbered files
• Copy&paste from rectangular selections in data tables (re?)enabled.
• All user actions are logged

Internal improvements:

• Qt signals are captured by widget wrappers. Everywhere else, Qt signals
  are replaced by explit function calls. All computation intensive data
  are cached. In this way, unnecessary computations are avoided. This
  results in a huge speed gain.
• For testing purposes, widgets can be driven from the command line
• Decoupled "highlighting" (one measurement group) from "selecting" (most or all measurements).
• Logic moved from table models to datasets.
• Unified exception handling.
• Doxygen comments for all files, namespaces, and classes.