Suggest windows and aws

Related to #92, it seems to me that full fledged dependencies on aws and windows is excessive for pure Linux environments. 

As suggested by @carmstrong, this change moves from depends to suggests for both aws and windows.

YMMV, but switching to suggests moved my chef setup from failing to compile (even though I cloned down the aws and windows cookbooks), to a working state where I am able to compile and run successfully.

If this patch is accepted, it should resolve #92 as well.