General code cleanup (#1029)

* Use lambdas where appropriate.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Use diamond operator where appropriate.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Use foreach.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Remove unused imports.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Remove a few redundant casts.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Code cleanup

- Name variables consistently
- Cleanup some whitespace
- Remove unneeded throws statements
- Remove some unused stuff

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Drop redundant 'OpenHAB' prefix from class names.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Update checkstyle config to better match our style.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Fix coding style issues.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Don't generate IDs in android package.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Improve some comments.

Signed-off-by: Danny Baumann <dannybaumann@web.de>

* Fix checkstyle issues in tests.

Signed-off-by: Danny Baumann <dannybaumann@web.de>