post-receive commit hooks receive on standard input lines of the form:
old-commit new-commit ref
old-commit new-commit ref
old-commit new-commit ref
so we can inspect those lines to determine whether or not the current
branch (aka HEAD) has been changed. because there's no reason to rebuild
the html representation of other branches.
in future we might even use the git tree-diff between old-commit and
new-commit to determine the set of files that have been added, removed,
or changed, and regenerate the html representation for only those files,
instead of deleting and rebuilding all files every time.
- removed old comments
- moved todos and nice-to-haves into the README.md's todos and hopes
- changed gobally mutated variables to be global constants. originally
these were mutated because the code was structured differently, and
allowed an option argument, specifying which bare git repo to use, but
i removed that, and forgot to remove and change the cruft
