Add MobileNet v1

[darsnack]

Adds MobileNet v1 for completeness.

[ToucheSir]

Suggested change

	function MobileNetv1(imsize::NTuple{2, Int} = (224, 224), width_mult = 1;
	function MobileNetv1(imsize::Dims{2} = (224, 224), width_mult = 1;

[theabhirath]

Hmm currently all the models use NTuple{2, Int} so maybe we'd have to change that across all occurrences for uniformity

[ToucheSir]

I wasn't sure if there were any scenarios where Int could be something else (some static type, maybe), so I held off from commenting on the earlier model PRs as they left the eltype out. Assuming none of those changes are released, we could always constrain everything to dims and loosen it up if the need arises.

[darsnack]

There are some which are not intended to be Dims but I left those as is. I did change the rest.

[darsnack]

There are one case (VGG) that has <:Integer and has been released, but hopefully this PR is straightforward enough to get in before v0.7 is released.

[darsnack]

There's some mismatch between the "large" tests in #132 and here. Since the tests appear to pass the MobileNet section and error later, I'd like to merge this (assuming no changes requested) and deal with memory issues in #132.

[darsnack]

Bump @ToucheSir?