Refactoring to allow associating more meta-data with R data structures.

...me/src/com/oracle/truffle/r/runtime/data/RBaseObject.java

...me/src/com/oracle/truffle/r/runtime/data/RExpression.java

...untime/src/com/oracle/truffle/r/runtime/data/RFactor.java

...time/src/com/oracle/truffle/r/runtime/data/RFunction.java

...untime/src/com/oracle/truffle/r/runtime/data/RGPBits.java

...time/src/com/oracle/truffle/r/runtime/data/RLanguage.java

....runtime/src/com/oracle/truffle/r/runtime/data/RList.java

...ntime/src/com/oracle/truffle/r/runtime/data/RPromise.java

...time/src/com/oracle/truffle/r/runtime/data/RS4Object.java

...untime/src/com/oracle/truffle/r/runtime/data/RScalar.java

...time/src/com/oracle/truffle/r/runtime/data/RSequence.java

...me/src/com/oracle/truffle/r/runtime/data/RTypedValue.java

...untime/src/com/oracle/truffle/r/runtime/data/RVector.java

...cle/truffle/r/runtime/data/closures/RToVectorClosure.java