Push improvements

[pyroskat]

Push has 1 single option" Push value. But this modifier could have much more options for better control:

-Push along normals options:  Only pushing along normals, doing an average with colateral normals, blend values, etc.

-Selfintersection on/off (avoiding self collision mesh when using push.

-I am sure we can think with more options.

[Kranos_Orphydian]

yeah maybe I will use it more that way

[Kranos_Orphydian]

bump for this!