Background Support

Problems:
- For some reason the css parser won't parse any characters other than letters. For example, properties like: content-box and no-repeat break this code.

- Default value for any longhand property is "initial"

- When converting back from longhand to shorthand, the new changes are not captured and saved (even though I used the same code that redmunds used). Instead, the "initial" value is saved for all values.

- There is an extra line at the end when converting from shorthand to longhand.