0.2.1

Bug fix:

• Removed fake cell style that are real data styles: no more pollution of named cell styles in LO
• Fixed issues in file save (e.g. user can be warned when a file exists before overwrite it)

New features:

• One can use links in text cells
• ConfigItems are (roughly) accessible: this may need some new methods in the API

Clean up:

• All generated files during the tests go in a specific dir
• Examples, benchmark and profiling sources are in a "misc" dir
• Naming: OdsFile becomes OdsDocument and OdsEntry becomes OdsElement
• The benchmark presentation gives a synthetic presentation of the results.