runtime+misc: move r5js.procs.newProcCall => r5js.newProcCall. Remove proc.js.
runtime: r5js.ProcCall: remove obsolete ctor comment.
runtime: make r5js.ProcCall.operatorName private.
runtime: make r5js.ProcCall.firstOperand protected.
runtime: make r5js.ProcCall.env protected.
runtime: make r5js.ProcCall#reconstructDatum private.
runtime: make r5js.ProcCall#tryMacroUse private.
runtime: make r5js.ProcCall#tryContinuation private.
runtime: make r5js.ProcCall#tryPrimitiveProcedure private.
runtime: make r5js.ProcCall#tryNonPrimitiveProcedure private.
runtime: make r5js.ProcCall#tryFFI private.