Makefile: fix missing files in release tarball, and install repobench

This merge request updates Makefile to:

1. include surgeon/svnread.go and repository-editing.adoc to allow make to work;
2. include lintfilter to allow make check to work;
3. install repobench and repobench.1

I did not include bench/* as I am not sure if you wanted that directory in the release tarball, so please feel free to further modify Makefile as you see fit.

Thanks!