3D connexion support on Linux:

- Replace hidapi/linux/hid.c with the hidraw variant (link to udev)
- Add CMakeLists.txt for hidapi, refactor
- Add udev rules file (no installation so far)

src/hidapi/CMakeLists.txt

@@ -0,0 +1,17 @@
+
+if (WIN32)
+    set(HIDAPI_IMPL win/hid.c)
+elseif (APPLE)
+    set(HIDAPI_IMPL mac/hid.c)
+else ()
+    # Assume Linux or Unix other than Mac OS
+    set(HIDAPI_IMPL linux/hid.c)
+endif()
+
+include_directories(include)
+
+add_library(hidapi STATIC ${HIDAPI_IMPL})
+
+if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    target_link_libraries(hidapi udev)
+endif()