Better styling, search, and user experience enhancements

• #227 Better edge styling configurability
• #222 Documentation header logo now links to homepage
• #221 Hovering on edges when not ".active" has no effect
• #220 Improved clone and build process
• #211 Search is now configurable between "contains" and "begins"
• #210 Selected nodes now deselect upon reclick
• BUG: #218 Node fill matches cluster color when cluster: true
• BUG: #213 alchemy.conf.initialScale is applied in all cases
• DOCS: #217 Documentation footer logo now a link
• DOCS: #226 and #224 Improved examples, including advanced styling based on node and edge properties.