Changed .NET version

Added logo, added nuget binaries and configuration and changed .NET
framework version to 4.0 (from 4.5).
Merged DocumentBuilder and NodeBuilder, fixed bug with references in attributes
Changed version number, added XML documentation output for release build.
A small change to attack a non-conformal closed anchor tag within the body correctly
Improved stylesheet integration
Pack unknown CSS rules ( like @-moz-... ) in an ignored rule
Visibility changed (keep internal stuff internal) and CSS values intermediate solution
Improved Html Tokens
Started playing around with an improved tokenization process.
Improved tokenization, merged source managers and made parsers look quite similar. Also prepared async. parsing (not included yet).
Updated comments, fixed some modifier issues (using internal for nearly everything as the W3C DOM specification tells us)
Decorated the CSS tokens more nicely.
Decreased footprint of CSS parser (slickspeed requires in total 3ms for all tests with everything), improved HTML DOM representation.
Continue on improving modifier update; extending documentation.
Updated documentation
Merged CssParser and CssRuleConstructor
Removed intermediate CSS objects and improved CSS parser.
Added CSS color names, extended CSS parser and prepared to include CSS values.
Finished a first stage of CSS parsing. Prepared everything for CSS Value parsing and started work on ToCss() methods.
Rearranged some files, improved on CSS values and added some tests for CSS values.