[MRG]Added has_fit_parameter method

Fixes #3711 
Ping @mblondel 
Sorry for contradicting myself but I know realize that this is quite redundant with the explanation above. So you can just remove the lines below. You can instead add an example.

```
Example
-------
>>> from sklearn.svm import SVC
>>> has_fit_parameter(SVC(), "sample_weight")
True
```