ENABLE_3DCONNEXION_DEVICES - 1st installment of support for 3Dconnexion devices

Implemented using hidapi library (https://github.com/libusb/hidapi) and https://github.com/koenieee/CrossplatformSpacemouseDriver/tree/master/SpaceMouseDriver as reference

Unsolved issues:

- When manipulating the SpaceNavigator wxWidgets generates a mouse wheel event that needs to be filtered out

- wxWidgets does not detect devices being connected/disconnected to the pc

- Current state forces a continuous rendering

- Current state misses dependence on camera zoom

- Non intuitive movement limits

- Translation and rotation speed factors are hardcoded

- Number of device buttons hardcoded

CMakeLists.txt

@@ -365,6 +365,25 @@ include_directories(${GLEW_INCLUDE_DIRS})
 add_library(cereal INTERFACE)
 target_include_directories(cereal INTERFACE include)
 
+# Find the hidapi library
+if(WIN32)
+add_library(hidapi STATIC
+    ${LIBDIR}/hidapi/win/hid.c
+)
+elseif (APPLE)
+add_library(hidapi STATIC
+    ${LIBDIR}/hidapi/mac/hid.c
+)
+else ()
+add_library(hidapi STATIC
+    ${LIBDIR}/hidapi/linux/hid.c
+)
+endif ()
+set(HIDAPI_FOUND 1)
+set(HIDAPI_INCLUDE_DIRS ${LIBDIR}/hidapi/)
+set(HIDAPI_LIBRARIES hidapi)
+include_directories(${HIDAPI_INCLUDE_DIRS})
+
 # l10n
 set(L10N_DIR "${SLIC3R_RESOURCES_DIR}/localization")
 add_custom_target(pot