[Conan] Re-add Qt.

conanfile.py

@@ -8,13 +8,15 @@ class OpenGeoSysConan(ConanFile):
         "Shapelib/1.3.0@bilke/stable", \
         "VTK/[>=6.3,<7.1]@bilke/stable", \
         "Eigen3/3.2.8@bilke/stable", \
-        "libgeotiff/1.4.1@bilke/stable"
+        "libgeotiff/1.4.1@bilke/stable", \
+        "Qt/5.6.2@bilke/testing"
 
     generators = "cmake"
 
     default_options = \
         "Boost:shared=False", \
-        "Boost:header_only=True"
+        "Boost:header_only=True", \
+        "Qt:xmlpatterns=True"
 
     def build(self):
         cmake = CMake(self.settings)