Add OpenGL libraries to test target link libraries (Washington-Univer…

…sity#86).

Ensures that OpenGL libraries are linked when building test targets, which may be necessary for proper rendering and testing of graphics-related functionality.

src/Tests/CMakeLists.txt

@@ -140,6 +140,7 @@ ${OSMESA_GLU_LIBRARY}
 ${Z5_COMPRESSION_LIBRARIES}
 ${ZLIB_LIBRARIES}
 ${OPENMP_LIBRARY}
+${OPENGL_LIBRARIES}
 #${LIBS}
 )