report main process version number on start

@mrdavidlaing, it reports data like this:

```
2014-11-27 09:42:41,388 [9] INFO  LogSearchShipper.LogSearchShipperService - { MainProcessVersion = 1.0.5444.30073 }
```

Looks ok for you?
@fandrei - could you find a way to link this version to the version passed in during the build please

[`/t:Build /t:RunTests /t:Package /p:BUILD_VERSION=${VERSION}-\${BUILD_NUMBER}`](
https://github.com/cityindex/labs-operations/blob/master/shared/releases/logsearchshipper.job-dsl.groovy#L34)