allow setting a job description

adding DESCRIPTION=foo to $JOBNAME.conf will display "foo"
in the job overview page on the frontend

Resolves #97

src/resources/index.html

@@ -228,6 +228,7 @@
    <div class="row">
     <div class="col-sm-5 col-md-6 col-lg-7">
     <h3>{{$route.params.name}}</h3>
+    <div v-html="description"></div>
     <dl class="dl-horizontal">
      <dt>Last Successful Run</dt>
      <dd><router-link v-if="lastSuccess" :to="'/jobs/'+$route.params.name+'/'+lastSuccess.number">#{{lastSuccess.number}}</router-link> {{lastSuccess?' - at '+formatDate(lastSuccess.started):'never'}}</dd>