Transition to wxWidgets 3.2 (Closes: #1019819)
This fixes the compile issues with qutemol and wxWidgets 3.2 (basically, qutemol was using an ancient wxGLCanvas API that was finally removed in wx 3.2). However, there is still an additional issue with incompatibility between glew and wxWidgets. See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1020640.