Rename repository

Hi @Ocramius ,

For homogeneity purpose with how composer name packages, I think it would be a good idea to rename the GitHub project from "DoctrineModule" to "doctrine-module". I tried it with my own projects, it's absolutely painless, it breaks nothing (even the old URL is redirected to the new one). It just provides more homogeneity and it seems like some projects like Doctrine adopte this (as well as zf itself).

(I'm not going to raise in issue but the same applies for DoctrineModuleORMModule, DoctrineModuleMongo...)

EDIT : in fact, the composer package canonical also needs to be updated on Packagist.