Fix #423, generalized SRT active surface sector thread. (#425)

* Fix #423, generalized SRT active surface sector thread.

The modifications have been tested with the AS simulator. The startup procedure along with the `asSetup` and `asPark` commands seem to work fine. Further testing with the antenna should confirm this consistent behavior.

* Fixed a typo that prevented a successful build

* Fixed some issues with sector number

* Fixed the cleanup procedure