Objective-J: Adopt general runtime fixes from the npm runtime

Executable.setCode failed when the compiler produced no code after a compile
error. This adopts that fix and the other general changes from the runtime
published to npm as @objj/runtime, without its Node-specific changes.

- CFDictionary.js: Add toJSObject, which returns the contents as a plain object
- Executable.js: Return early from setCode when no code was produced
- CPLog.js: Return early from CPLogPrint when CPLogDisable is set
- Bootstrap.js: Accept SourceMapIncludeSource in OBJJ_COMPILER_FLAGS

Objective-J/Executable.js

@@ -219,6 +219,8 @@ Executable.prototype.setCode = function(code, sourceMap)
 {
     this._code = code;
 
+    if (code == null) return;
+
     var parameters = this.functionParameters().join(",");
     var sourceMapBase64;