Extracted the shadow class, added text-shadow property and fixed a bug in the ToString() method of the Color struct
Added files
Adjusted color tests (using PureGreen, since Green is now the HTML defined one)
More tests for CSS error correction
More CSS malformed decl. tests
Improved CSS factory to return created properties (override)
Fixed closing properties and initialized configuration
Improved source manager (decoupled from IConfiguration, depending on initial encoding)
Fixed bug when setting the important attribute