[backend] fix z/VM build job kill
[backend] Sync vm-disk/swap defaults with build

Build and bs_worker had different defaults on
vm-disk/swap, which caused e.g. job killing to
not work correctly if only defaults were used
(only happens in default installations, not
in our production setup).
[backend] support a proxy server for getbinaries for workers with a too small binary cache
[backend] getbinariesproxy implementation
[webui] There is no reason to hide our awesome users
[api] Get rid of the registration notes

Fixes #219
[webui] Update Gemfile.lock, fix all routes test
[backend] add help for --getbinariesproxy, fix typo
[api] revert incompatible change, but allow to register users without a note element

This reverts commit 262becb195fa9e71b69e61a15f8c049559401470.
[backend] hrm, the typo fix contained another typo. now all typos are gone.
[backend] improve ARGV handling in bs_getbinariesproxy and bs_srcserver