Actually spread out over several days..

I think I have finally comprehensively dealt with all the wacky system
misconfigurations that can make `git commit` complain and refuse to commit.
The last of these is [a system with a FQDN that doesn't have a dot in it](http://git-annex.branchable.com/bugs/view_logs_fails:_Internal_Server_Error__internal_liftAnnex/). 
I personally think git should just use the hostname as-is in the email
address for commits here -- it's better to be robust. Indeed, I think it
would make more sense if `git commit` never failed, unless it ran out of
disk or the repo is corrupt. But anyway, `git-annex
init` will now detect when the commit fails because of this and put a
workaround in place.

Fixed a bug in `git annex addurl --pathdepth` when the url's path was
shorter than the amount requested to remove from it.

Tracked down a bug that prevents git-annex from working on a system with an
old linux kernel. Probably the root cause is that the kernel was built
without EVENTFD support. Found a workaround to get a usable git-annex on
such a system is to build it without the webapp, since that disables the
threaded runtime which triggered the problem.

Dealt with a lot of Windows bugs. Very happy that it's working well enough
that some users are reporting bugs on it in Windows, and with enough detail
that I have not needed to boot Windows to fix them so far. ;)