Add a separate LICENSE file.

Fixes #197.

LICENSE

@@ -0,0 +1,27 @@
+
+RtAudio: a set of realtime audio i/o C++ classes
+Copyright (c) 2001-2019 Gary P. Scavone
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation files
+(the "Software"), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software,
+and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+Any person wishing to distribute modifications to the Software is
+asked to send the modifications to the original developer so that
+they can be incorporated into the canonical version.  This is,
+however, not a binding provision of this license.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -35,31 +35,4 @@ For complete documentation on RtAudio, see the doc directory of the distribution
 
 ## Legal and ethical:
 
-The RtAudio license is similar to the MIT License.
-
-    RtAudio: a set of realtime audio i/o C++ classes
-    Copyright (c) 2001-2019 Gary P. Scavone
-
-    Permission is hereby granted, free of charge, to any person
-    obtaining a copy of this software and associated documentation files
-    (the "Software"), to deal in the Software without restriction,
-    including without limitation the rights to use, copy, modify, merge,
-    publish, distribute, sublicense, and/or sell copies of the Software,
-    and to permit persons to whom the Software is furnished to do so,
-    subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be
-    included in all copies or substantial portions of the Software.
-
-    Any person wishing to distribute modifications to the Software is
-    asked to send the modifications to the original developer so that
-    they can be incorporated into the canonical version.  This is,
-    however, not a binding provision of this license.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
-    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
-    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+The RtAudio license is similar to the MIT License.  Please see [LICENSE](LICENSE).