Refactor, unit tests, npm updates, navbar

[DoctorBud]

• This commit refactors the initial table-editor to be more maintainable and extensible, including the use of unit tests, SCSS, and Angular components.
• It also extends the application to support a navbar and a help/settings screen.
• The application state is now isolated into an angular service, so that state is maintained during routing between navigation tabs.
• The yaml and xsv URL parameters are now updated and respected properly
• Adds a placeholder branding logo image
• Trims the navbar height down
• Use SCSS and bootstrap-scss to allow better customization of styles
• Update many of the NPM modules used.
• Adopt PostCSS for CSS preprocessing (faster than using outboard LESS and SCSS tools).