[MRG+1] Change loss names for LinearSVC and LinearSVR

the names are now consistent across methods and with the SGD module

In LinearSVC:
   'l1' -> 'hinge'
   'l2' -> 'squared_hinge'
In LinearSVR:
   'l1' -> 'epsilon_insensitive'
   'l2' -> 'squared_epsilon_insensitive'
Ohh, missed this one. I too think we should do this in `fit` and not actually store the translated loss name. Just make sure `l1` and `hinge` cause the same behavior.