Don't link to Xlib's Xrender library

We don't use this library in XCB plugin.

Change-Id: Ifcc2f404b3cbf5601eb094eaac923d2f9e6e981b
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
QSwipeGestureRecognizer: Prevent cancel in startup-phase.

Replace the boolean 'started' member by an enumeration which indicates
the startup phase. While in that phase, do not cancel when pressed
points are detected for fewer than 3 touch points.

Task-number: QTBUG-15768
Change-Id: Ic57b19e3002392fb632f551f615d80ada9831d34
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Doc: Corrected autolink errors qtbase

Task-number: QTBUG-40362
Change-Id: I054a4713bdd83280be51697689e0c3c3409b9601
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Doc: Corrected identifiers for  QByteArray::toBase64 in snippet

Task-number: QTBUG-40944
Change-Id: I31fc23739b3e145b3668b10fdf4465c19d2fdb01
Reviewed-by: Martin Smith <martin.smith@digia.com>
Doc: link to MIBenum

Task-number: QTBUG- 40362
Change-Id: I0261117d8aef8383ef77887a201d61ed0bd0ba52
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>