Update README and add LICENSE

Author: ronaldtse

LICENSE.adoc

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+= Licenses & Copyright
+
+This license file adheres to the formatting guidelines of
+https://github.com/nevir/readable-licenses[readable-licenses].
+
+
+== Ribose BSD 2-Clause License
+
+Copyright (c) 2020, [Ribose Inc](https://www.ribose.com).
+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.
+
+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.
+

README.adoc

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+= EXPRESS grammar in ANTLR4
+
+//image:https://github.com/lutaml/expressir/workflows/ubuntu/badge.svg[ubuntu]
+//image:https://github.com/lutaml/expressir/workflows/macos/badge.svg[macos]
+//image:https://github.com/lutaml/expressir/workflows/windows/badge.svg[windows]
+
+== Purpose
+
+This is the EXPRESS grammar file according to ISO 10303-11, and is
+tested to work with all ISO 10303 SMRL EXPRESS files that are
+valid.
+
+These files in SMRL have been determined to be deviated from the grammar
+and are therefore invalid.
+
+== Contributing
+
+First, thank you for contributing! We love pull requests from everyone. By
+participating in this project, you hereby grant
+https://www.ribose.com[Ribose Inc.] the right to grant or transfer an unlimited
+number of non exclusive licenses or sub-licenses to third parties, under the
+copyright covering the contribution to use the contribution by all means.
+
+Here are a few technical guidelines to follow:
+
+* Open an https://github.com/lutaml/expressir/issues[issues] to discuss a new
+  feature.
+* Write tests to support your new feature.
+* Make sure the entire test suite passes locally and on CI.
+* Open a Pull Request.
+* https://github.com/thoughtbot/guides/tree/master/protocol/git#write-a-feature[Squash your commits] after receiving feedback.
+* Party!
+
+
+== License
+
+This grammar is developed by Ribose Inc. and open sourced under a BSD-2 clause license.
+
+== Credits
+
+We thank the support provided by NIST, Boeing and ISO/TC 184/SC 4/TF 1.