Genice

* svg_poly module.

* Ring phase statistics.
* Radial Kirkwood G function.
* Some plugins accept options using brackets.
* Cell reshaper.
* Added the current working path as a searchpath for the plugins.
* Aeroice generator.
* Accept the structure that does not obey the ice rules.

* Bug fix in case the atomic number exceeds 100 000 in Gromacs format.

* Simulation cell-related functions are separated to a module.

* Adapted to NetworkX 2.

* Regulated the value range of Euler's angles.