Android: Refactor exception checking in qjni.

In places where we call java/jni functions that can throw exceptions,
we check and clear the exception, if necessary. This change moves
the "checking" code into a single (private) function.

Change-Id: Ic3de2be51305972b096e1ed0a477e341eb5d9404
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Doc: removed trolltech.com from namespace in manual qdocconf file

Task-number: QTBUG-23270
Change-Id: Id65ded1adbbb4f15ef5634f9a984c6cfad5c18d5
Reviewed-by: Martin Smith <martin.smith@digia.com>
Fix for code snippet in commandlineparser documentation

One line in the code snippet wasn't translated whlie the others were.

Change-Id: Ie77a317833f800087b485609cd001dd26060a40f
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>