Compiler overhaul

Problems with current impl:

• too monolithic
• user facing protocol
• functions that don't fit on one page

Goals:

• Intermediate form should more closely resemble an RA AST
• Optimization (like using a single SELECT for multiple RA primitives) during compilation
• More extensibility: Protocols in syntactic positions
  • Using DB extensions w/o introducing a new dialect (dialect is "column" vs column, IMO)
• Caching of compiled AST fragments