Updated LICENSE file

Added "Contributors" to copyright and note explaining where to find list of them.
Added note to top of file explaining source code files can contain a license that takes precedence over license in this file
Added license text delimiters

Author: delphidabbler

csdb/v4.16/collection/LICENSE

@@ -1,7 +1,14 @@
-MIT License
+All snippets in this collection are licensed under the MIT license (see below)
+UNLESS the snippet contains contrary licensing information in its source code
+file, in which case that license applies to that snippet only
+
+MIT License
 -----------
 
-Copyright (c) 2020 Peter Johnson <https://en.gravatar.com/delphidabbler>
+>> Begin license text
+
+Copyright (c) 2020 Peter Johnson <https://en.gravatar.com/delphidabbler> and 
+Contributors. 
 
 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
@@ -19,3 +26,10 @@ 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.
+
+<< End license text
+
+Note
+----
+
+The contributors mentioned above are listed in the CONTRIBUTORS file.