Doc: fix link to Getting Started from front page

The link to next page pointed to the wrong page.

Change-Id: I5544df8ed2ef64aa98ae356d7e2a33c968794302
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
CrashHandler: Link fix

Message box uses QTC_ASSERT nowadays.

Change-Id: I202d934eda7803a6137b2722008919d9f8136381
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>