Advanced Search + Refactoring

[raphaelhoffmann]

This is a fairly big overhaul of the frontend which also adds a bunch of new features:

• ability to create bulk search queries
• ability to switch between basic and advanced query modes (this switch happens automatically whenever necessary)
• adds a parser for lucene query syntax; allows us to perform transformations and check if a query is simple or advanced
• advanced queries support OR, AND, ||, &&, +, -, (, )
• basic implementation of lightweight suggestions (currently not enabled)