stop ignoring version.h
generated for the last time, maybe
stop using version.h.in for cmake
Merge branch 'no-version'

We can modify version.h directly, as desired. It is retained for
backward-compatibility, in case anyone is using those macros.

Note: I have not modified SConstruct since that is deprecated, so
I have retained the `version` file, which should be ignored.

Addresses issue #38