rewrite Community class and internal data handling

[knaaptime]

this is a rewrite of the community class, as discussed here, to be more lightweight and transparent. I also renamed a few functions for clarity and changed the way the internal data handling works. Should be a lot more efficient this way

tests are passing locally, but i am having trouble getting the quilt stuff stable on travis

[renanxcortes]

Not sure if this is the case, but have you tried add numpy to the environment.yml?

[knaaptime]

The new way Travis is setup, it is only using the requirements files and not even reading the environment.yml