rework BinaryJSON expressions

• remove distinction with fixed lengths of fields (the sizeOfLengths), because it results in large binary size (subfields does not work reliable if the sizeOfLengths differ between subobject and parent object);
• allow slicing expressions in evaluation expression, by starting with '{' OR '['
• support slicing in slicing expression:
  {title: value+1, body: {a: subobject.c+2, b: subobject.d+3}}
• support new slicing context:
  {title: value+1, body: subobject -> {a: c+2, b: d+3}}
• support R"( syntax for raw string literals
• support "key":value in slicing expression (opposed to key:expr)
• support | for raw string literals with indentation
• make \n behave as , for object definitions (if {\n is seen?)
• support c ? a : b expressions