Improve @import and @media

New features:

• remove unreachable @import files
• transform @import url media to @media type {rules}

Existing features:

• Remove white space and extra characters
• * whitespace
• *Last semicolon in a statement
• *Measurement units for the values (eg margin: 0px -> margin: 0)
• Comments (preserving /! important comments */)
• *Empty statements (eg p {})
  Use shorthand properties
• *margin
• *padding
• *border
• *outline
• *list-style
• *background (eg instead of background-color)
• Compress colors
• *Use short notations of hexadecimal colors (Ex: color: # ff6600 becomes color: # f60;). Use colors supported in CSS 2 whose name is shorter than the hexadecimal.
• Sorting CSS properties
• Merge properties
• merge rules if required
• @import CSS
• @media queries CSS