Android: Qt 5.2 deployment add a button to create a Android manifest

The AndroidManifest.xml is no longer needed in as many use cases as
before. So the new deployment does not automatically create a
android manifest. Offer a button on the deployment page to create
a android manifest. This also edits the .pro file adding the
ANDROID_PACKAGE_SOURCE_DIR.

Change-Id: I2655dd6c96e2087732b4d7240b31fe9fcf168600
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
CppEditor: findLinkAt() delegates to FollowSymbolUnderCursor

Moves functionality of CPPEditorWidget::findLinkAt into a newly created
class FollowSymbolUnderCursor. This slim downs cppeditor.cpp a bit and
makes Follow Symbol Under Cursor more easily testable.

Change-Id: I106c7fbfc6869dd13c75381fbe87c90dc88998a7
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>