Add glfwConfig module.

This module allows cmake projects to find glfw with FIND_PACKAGE.

src/glfwConfig.cmake.in

@@ -0,0 +1,10 @@
+# - Config file for the glfw package
+# It defines the following variables
+#   GLFW_INCLUDE_DIR, the path where GLFW headers are located
+#   GLFW_LIBRARY_DIR, folder in which the GLFW library is located
+#   GLFW_LIBRARY, library to link against to use GLFW
+
+set(GLFW_INCLUDE_DIR "@CMAKE_INSTALL_PREFIX@/include")
+set(GLFW_LIBRARY_DIR "@CMAKE_INSTALL_PREFIX@/lib@LIB_SUFFIX@")
+
+find_library(GLFW_LIBRARY "@GLFW_LIB_NAME@" HINTS ${GLFW_LIBRARY_DIR})