Adding documentation and license to FindComputeCpp

This patch adds some licensing and documentation information for the FindComputeCpp module in order to easily re-distribute the FindComputeCpp file without the rest of the SDK.

cmake/Modules/FindComputeCpp.cmake

@@ -1,13 +1,34 @@
 #.rst:
 # FindComputeCpp
 #---------------
+#
+# Copyright 2016 Codeplay Software Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use these files except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# For your convenience, a copy of the License has been included in this
+# repository.
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 #########################
 # FindComputeCpp.cmake 
 #########################
 #
 # Tools for finding and building with ComputeCpp.
 #
+# User must define COMPUTECPP_SDK_ROOT pointing to the ComputeCpp installation.
+# 
+# Latest version of this file can be found at:
+# https://github.com/codeplaysoftware/computecpp-sdk
 
 # Require CMake version 3.2.2 or higher
 cmake_minimum_required(VERSION 3.2.2)