allow to load pretrained weights when the include_top variable is False

[kurnianggoro]

This merge request is related to the bug #278

The class initialization is failed when called using from_pretrained(.., include_top=False) function or when the number of classes is not equal to 1000, i.e. from_pretrained(.., num_classes=100).

This pull request allow to load the pre-trained weights even when the number of classes is not equal to 1000 or when the top classifier is ignored.

_fc.weight and _fc.bias will only be loaded when include_top=True and num_classes=1000 (default values)

[spirosbax]

Why hasn't this been merged yet? A simple solution to a problem affecting many users.