Modified plugins to use Qt4 or Qt5 depending on the global configuration

Change-Id: I104bcf927c74c5f84b975f8d5c0df9f3964a9064
Use the new Qt5 plugin architecture

Q_EXPORT_PLUGIN2 deprecated. Replaced by Q_PLUGIN_METADATA
Find the Qt5 RCC executable to generate qrc_* files.

Change-Id: I86e6664e85015e3817d80d5dad1b04deeffe1459
Updated QtTesting to use Qt5

QtTesting should use user selected Qt version
Change-Id: I22337268e9864b5fe2153309f6844cdf3ab4e4b3
WIP: Restore Qt4 and enable option to build against Qt5

Change-Id: If3cb97ff798b22a5fb4e89c0be948ca6b65ee1d1
Fixed examples to use Qt4 or Qt5 depending on user preference

Change-Id: Ieb302552284d52ed61a4f552ec4526c176392af8
Fixed ParaView macros to use both Qt4 and Qt5

Change-Id: I595069f00809082e30770e0c3e2dcd14ef8f69ae
Include ParaViewQt5.cmake instead of doing find_package(Qt5)

Change-Id: Ia356394db4c876eeeccc42845af5156749e97479
Reverted macros to use both Qt4 and Qt5

Change-Id: Ibf7b9d492b170232d3f5649ac6a0a14f4da95dd4
Import Qt5Widgets module at the top level

This ensures all the required Qt5 variables can be found.
For example, just importing Qt5Core does not help find QT_UIC_EXECUTABLE using
the macro "get_target_property(QT_UIC_EXECUTABLE Qt5::uic LOCATION)". This must
be a Qt5 bug.

Change-Id: Ie6f4a708682ad8cf2391d218c193d8127e4c44f7