[Headlights] Log startup and plugin loading messages distinctly from version messages

```
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Auto startup: generator-core" time="2014-04-16T17:54:32Z" seq="53" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Version: 3.0.0-dev" time="2014-04-16T17:54:32Z" seq="54" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin loaded: generator-assets" time="2014-04-16T17:54:33Z" seq="64" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin version: generator-assets:2.0.0-dev" time="2014-04-16T17:54:33Z" seq="65" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin loaded: generator-assets-automation" time="2014-04-16T17:54:33Z" seq="84" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin version: generator-assets-automation:0.0.1" time="2014-04-16T17:54:33Z" seq="85" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin loaded: generator-weblogger" time="2014-04-16T17:54:33Z" seq="86" />
<EventRec doc="0" category="Scripting" subcategory="Generator" name="Generator: Plugin version: generator-weblogger:0.0.1" time="2014-04-16T17:54:33Z" seq="87" />
```

CC @joelrbrandt