Release 0.6.0

Breaking Changes:

• style.get_class_name() no longer consumes the style and returns a &str
  instead of an owned string.
• Seed Integration is Removed.

Other Changes:

• Added Style::new which does not require a component name.
• Aesthetically pleasing Class Name.
• Replaced lazy_static with once_cell.
• Updated nom to v6.
• Updated Yew to v0.18.
• Removed Unnecessary Clones
• Optimised for Performance