Cleanup MANIFEST and include LICENSE
We didn't include the LICENSE file, the version file no longer exists, and the patterns on the inclusion of example was out of date and the examples wouldn't run.
As a reminder, this file controls what makes it into the wheel and tarball from PyPI.
-recursive-include cocotb/share *.c* *.h *.def Makefile.* Makefile
-recursive-include examples *.v *.py Makefile *.tcl *.cfg
-include version
+recursive-include cocotb/share *
+recursive-include examples *
include README.md
+include LICENSE
include cocotb_build_libs.py
