Bug 1026706.  Stop pickling our yacc grammar in the WebIDL parser, because now it's apparently faster to recreate it than to unpickle it.  r=khuey
Bug 1026080 part 1.  Add WebIDL parser support for [] as a default value for sequence arguments and dictionary entries.  r=khuey
Bug 1026080 part 2.  Add binding codegen support for [] as a default value for sequence arguments and dictionary entries.  r=khuey
Bug 767924 part 1.  Add support for holders with nonempty holderArgs in unions.  r=peterv
Bug 767924 part 2.  Introduce both const and non-const versions of GetAs* methods on unions, with the former returning the public-facing type and the latter returning the internal type.  r=peterv
Bug 767924 part 3.  Allow sequences in unions.  r=peterv
Bug 767924 part 4.  Allow [] as a default value for sequences in unions.  r=peterv
Bug 1023762 part 1.  Factor out the IDL-to-C++ type mapping for event codegen into a separate function.  r=smaug
Bug 1023762 part 2.  Add basic support for sequences of non-containers to event codegen.  r=smaug
Bug 1027667.  Allow MozMap in unions.  r=peterv