[FIX] Fix deadlock problems

Add some fixes to avoid deadlock problems.

- Shutdown eventu module after other user modules
- Add some instance checks in eventkcal_linuxkernel.c
- Add missing circbuf_unlock() in circbuf_readData()

Change-Id: I23600e41b8698fe9b10e50627ec65da9d66aa206
Reviewed-on: http://brateggevoat1/gerrit/2290
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Joerg Zelenka <joerg.zelenka@br-automation.com>
Reviewed-by: Wolfgang Seiss <wolfgang.seiss@br-automation.com>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[FIX] Remove some more "epl" where appropriate

Change-Id: Iedca658f45c1670270a7289631def0cf4684d2a3
Reviewed-on: http://brateggevoat1/gerrit/2296
Reviewed-by: Wolfgang Seiss <wolfgang.seiss@br-automation.com>
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[FEATURE] Add callback function for PDO change events in pdou.c

The callback is called when a PDO is enabled or disabled. The affected
mapped objects can be read from the OD during the callback function.

This change is based on change for V1.08.3 from
Daniel Krueger <daniel.krueger@systec-electronic.com>

Change-Id: I47674c793bf086d6fce974991ca2aaff7d0b6300
Reviewed-on: http://brateggevoat1/gerrit/2292
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Wolfgang Seiss <wolfgang.seiss@br-automation.com>
Reviewed-by: Joerg Zelenka <joerg.zelenka@br-automation.com>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[FEATURE] Add support for PDO change events to API

This change is based on change for V1.08.3 of
Daniel Krueger <daniel.krueger@systec-electronic.com>

Change-Id: I41f9bac702c0836a2f7a38bd96f179084c79c2aa
Reviewed-on: http://brateggevoat1/gerrit/2293
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[FEATURE] Add support for PDO change events in demo applications

This change is based on change for V1.08.3 from
Daniel Krueger <daniel.krueger@systec-electronic.com>

Change-Id: If7d0e9bd274d1f1329bd3fe48c9f433517bb720c
Reviewed-on: http://brateggevoat1/gerrit/2294
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Wolfgang Seiss <wolfgang.seiss@br-automation.com>
Reviewed-by: Joerg Zelenka <joerg.zelenka@br-automation.com>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>