Release 1.1

Prepare for release 1.0

* various bug fixes

* molmod.randomize: tools for making random molecular geometries
* coincide in molmod.transformations: a function that finds the optimal overlap
  between two molecular structures with the same topology and a similar
  geometry.
* extra file formats: CubeReader (gaussian), HistoryReader (dl_poly),
  OutputReader (dl_poly), DumpReader (lammps),
* a few extra units (conversion factors in molmod.units)

* Bug fix release (updates and improvements in molmod.io)

* Initial release.