Allow pqApplicationComponentsInit in non-static builds.
PV needs to call pqApplicationComponentsInit() to initialize QT
resource only for static builds. However, if client apps want to
re-use ParaView QT resource for their own menus/toolbars, they
need to call pqApplicationComponentsInit() always, even for shared
builds. Move the #if !BUILD_SHARED_LIBS
guard so this is possible.
Also add a pqWidgetsInit()
so it works correctly for a shared build.