IMPORTANT: GNU 3.0 license was replaced with Apache 2.0 in ALL files

* SgmlParser.cs: removed variables that were assigned to, but never used
* SgmlReader.cs: removed variables that were assigned to, but never used
* ReadMe.md:
** Added release history
** Update license text
Updated version number to 1.8.9
Consolidated read me files
Cleaned up solution and project files
Merge pull request #6 from bjorg/master

Updates for 1.8.9 release