Changed testconf to tempest.conf, changed HistInterval to Delay in conf

Now include a tempest.conf.example for people to look at, but no tempest.conf, considering it has email addresses in it.
Added support to readings to deal with errors
Did go fmt on web.go, also added AjaxOnRun. Fixed TempestData.Running

AjaxOnRun is a meta-handler which returns a do-nothing handler if
there is not a current run, or the handler passed in if there is a current run
Alerts now only fire once per sensor per alert delay
Additions to .gitignore
*Actually* fix AjaxOnRun() and TempestData.Running

I must have been oxygen-deprived when I wrote 9ee5fe7...