Updated README.md to utilize markdown

README.md

 SimpleKit-ruby is a minimalist Ruby library which implements discrete event
 simulation using event graphs.
 
-Copyright (C) 2012-2017  Paul J. Sanchez
+Copyright (C) 2012-2018  Paul J. Sanchez
 
 This library is free software; you can redistribute it and/or
 modify it under the terms of the MIT free software license.
 
-This library is distributed in the hope that it will be useful,
+**This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.**
 
-DESCRIPTION
+### DESCRIPTION
 
 SimpleKit-ruby is a very minimal Ruby implementation of discrete event
 simulation based on Lee Schruben's "Event Graph" approach.  I wrote it
@@ -19,25 +19,22 @@ use it as long as you clearly understand that it was designed as a
 teaching tool.  For serious simulation modeling with event graphs I
 recommend Lee Schruben's SIGMA package or Arnie Buss's SimKit.
 
-WHAT'S WHAT
+### WHAT'S WHAT
 
-This top level folder contains this file, "ReadMe.1st", the
-simplekit.gemspec used to create the gem installation.
+This top level folder contains this file, `README.md`, and the
+`simplekit.gemspec` used to create the gem installation.
 
-To install SimpleKit-ruby, use Ruby's "gem" command:
+To install `SimpleKit` for Ruby, use Ruby's `gem` command:
 
 	gem build simplekit.gemspec
 	gem install simplekit-<version>.gem
 
-You may need to authenticate as an administrator to install gems.
+(You may need to authenticate as an administrator to install gems.)
 
-There are two subdirectories.  Source code for SimpleKit-ruby can be found
-in lib/simplekit.rb.  Documentation can be generated using Ruby's
-rdoc command.
+There are two subdirectories.  Source code for `SimpleKit` can be found
+in `lib/simplekit.rb`.  Local documentation can be generated using Ruby's
+`rdoc` command or `yard`.
 
-The second subdirectory is "demos", and contains three simple models to
-illustrate SimpleKit-ruby usage.  "MyModel.rb" demonstrates basic event
-scheduling and halting the model.  "MyModelArgs.rb" uses random times
-for the event scheduling, and shows how to schedule with arguments for
-the event methods.  Finally, "MMk.rb" implements an M/M/k queueing
-model.
+Examples can be found in the `demos` folder, which contains several relatively simple models to
+illustrate `SimpleKit` usage.  These include samples of
+event scheduling, both with and without arguments, and event cancellation.