Updated Scala FIRRTL with Testing and Infer-Types Pass

Reorganized Primops (renamed from PrimOps), added maps and functions to convert object <=> string, added eqv and neqv

Added infer-types pass, seems to work. Added infer-types error checking, modified Logger slightly, added Primops object for utility functions, minor changes in Utils

Modified getType to return Type rather than Option[Type] which makes more sense for some applications, also fixed up printing to better match stanza implementation

Moved Logger to new private object DebugUtils, changed UInt/SInt value printing to match stanza implementation

Added initial support for debug printing for lit based testing, most types of printVars still missing. Added Logger class for debug printing

Added support for no width to mean unknown, and print nothing instead of <?> for unknown width. Also added test to check this

Changed DefMemory to be a non-vector type with a size member

Conflicts:
	README.md

Add Scala implementation to firrtl repo

Merged in Scala implementation of FIRRTL IR, parser, and serialization (ie. AST -> String). Uses ANTLRv4 to generate concrete syntax parser

Change of FIRRTL semantics!

Fix init accessor

Assignments to a register are no longer affected by enclosing when
statements:

when p :
  reg r : UInt,clk,reset
  r := a

will lower to:

reg r : UInt,clk,reset
r := a

instead of:

reg r : UInt,clk,reset
when p : r := a

Make Link.fir reference relative path

Added DecToIndexer/DecFromIndexer. Fixed most use cases of incorrect catching of initialization of accessors. Missing use case of accessing an accessor. Still need to update tests to pass

Added a conditional readport example, with new idea of representing a read enable with muxing the index with poison bits