Add a multitude of sceNet* stubs.
I tried this in an attempt to fix the Peace Walker hangs, but it didn't seem to help, so it must be related to something else.
Remove useless dependency in FunctionWrappers.h.
Fix sceNetEtherNtostr.
Merge pull request #2070 from thedax/sceNetStubs

Implement multiple stubs for sceNet*