added server.commit_delay to mineos.conf

commit delay relocated from mc() to cron() and now will be read from
mineos.conf with a fallback of 10 seconds if: a) not an integer or b)
absent in config
rewrote check_interval

check_interval now can restart servers. the following options are valid
in server.config:
restart_interval
backup_interval
archive_interval
restart_interval uses dropdown in webui

upon detecting restart_interval in server.config, the web-ui will show
the same dropdown as archive/backup
new server gets restart_interval in webui
corrected issue with restart_interval

entire restart_interval process would fail if commit() or 'stop' were
executed to downed servers.  script will now gracefully handle an
unexpected downed server and continue the process, starting the server
if necessary.
changed default base_dir in server.py

base_directory changed to /var/games/minecraft, where every distro will
store the mineos skeleton. This will save the user from having to
provide -d when manually testing/starting up the server daemon
Merge pull request #35 from hexparrot/commitdelay

Commitdelay