Migrate to .NET 6.0 (the next .NET LTS release)

LICENSE.txt

@@ -1,10 +1,34 @@
-Copyright 2020 Raising the Floor - International
+BSD 3-Clause License
+
+Copyright 2020-2021, Raising the Floor - US
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. 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.
+
+3. Neither the name of the copyright holder 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 HOLDER 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.
 
-Licensed under the New BSD license. You may not use this file except in
-compliance with this License.
 
-You may obtain a copy of the License at
-https://github.com/GPII/universal/blob/master/LICENSE.txt
 
 The R&D leading to these results received funding from the:
 * Rehabilitation Services Administration, US Dept. of Education under 
@@ -19,4 +43,4 @@ The R&D leading to these results received funding from the:
 * Ontario Ministry of Research and Innovation
 * Canadian Foundation for Innovation
 * Adobe Foundation
-* Consumer Electronics Association Foundation
+* Consumer Electronics Association Foundation