msvs: fix install of codec sources

The libs.mk file must be installed for the vpx.vcproj file to be
generated. It was being installed, but not in the src/ directory as
expected.

Also missed include files yasm.rules, quantize_x86.h

Change-Id: Ic1a6f836e953bfc954d6e42a18c102a0114821eb
3 files changed