QVector: always grow exponentially

QVector: always grow exponentially

For non-movable types (QTypeInfo<T>::isStatic), QVector would grow the
array linearly, and defer to qAllocMore otherwise. That property,
however, gives no indication as to how the vector will grow.

By forcing additional allocations for growing containers of such types,
this penalized exactly those objects which are more expensive to move.

We now let qAllocMore reign in growth decisions.

Change-Id: I843a89dcdc21d09868c6b62a846a7e1e4548e399
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>