Fix copyright (#63)

Adds additional copyright for the MapLibre project.

LICENSE.txt

@@ -1,4 +1,4 @@
-Copyright (c) 2020, Mapbox
+Copyright (c) 2020, MapLibre
 
 All rights reserved.
 
@@ -10,7 +10,7 @@ are permitted provided that the following conditions are met:
     * Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.
-    * Neither the name of Mapbox GL JS nor the names of its contributors
+    * Neither the name of MapLibre GL JS nor the names of its contributors
       may be used to endorse or promote products derived from this software
       without specific prior written permission.
 
@@ -27,6 +27,38 @@ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
+-------------------------------------------------------------------------------
+
+Contains code from mapbox-gl-js v1.13 and earlier
+
+Version v1.13 of mapbox-gl-js and earlier are licensed under a BSD-3-Clause license
+
+Copyright (c) 2020, Mapbox
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+* Neither the name of Mapbox GL JS nor the names of its contributors
+  may be used to endorse or promote products derived from this software
+  without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
 -------------------------------------------------------------------------------
 
 Contains code from glfx.js