Various bug fixes. Also new features:
a) Manual run buttons. Those are on job and watch configuration pages, as well as button to run all watches on the configuration page.
b) Thread control. Set how many jobs to have in the queue at a time so you can run cron as often as you like without killing your job handlers.
c) Retry control. Set if you want jobs that failed with errors to retry, and if so how often.
d) Timeout control. For long jobs to avoid getting killed by php timeout settings.
