Polylx

* Examples added to distribution

* Sample neighbors_dist method to calculate neighbors distances
* Grains and Boundaries nndist to calculate nearest neighbors distances
* Fancy indexing with slices fixed
* Affine transformations affine_transform, rotate, scale, skew, translate
methods implemented for Grains and Boundaries
* Sample name atribute added
* Sample bids method to get boundary id's related to grain added

* PolyShape name forced to be string
* Creation of boundaries is Grains method

* classification is persitant trough fancy indexing
* empty classes allowed
* bootstrap method added to PolySet

* Smooth and simplify methods for Grains implemented
* Initial documentation added
* `phase` and `type` properties renamed to `name`

* First release