Further enhancements to factor and data frame support.

...oracle/truffle/r/nodes/builtin/base/DynLoadFunctions.java

.../com/oracle/truffle/r/nodes/builtin/base/LaFunctions.java

...rc/com/oracle/truffle/r/nodes/builtin/base/Structure.java

.../com/oracle/truffle/r/nodes/builtin/base/TypeConvert.java

.../src/com/oracle/truffle/r/nodes/builtin/base/UnClass.java

...c/com/oracle/truffle/r/nodes/builtin/base/UpdateAttr.java

...oracle/truffle/r/nodes/builtin/base/UpdateAttributes.java

.../com/oracle/truffle/r/nodes/builtin/base/UpdateClass.java

...m/oracle/truffle/r/nodes/builtin/base/UpdateOldClass.java

...racle/truffle/r/nodes/builtin/base/UpdateStorageMode.java

...le/truffle/r/nodes/access/array/read/AccessArrayNode.java

...m/oracle/truffle/r/nodes/binary/BinaryArithmeticNode.java

.../com/oracle/truffle/r/nodes/binary/BinaryBooleanNode.java

...le.r.runtime/src/com/oracle/truffle/r/runtime/RError.java

....runtime/src/com/oracle/truffle/r/runtime/RSerialize.java

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

...e/src/com/oracle/truffle/r/runtime/data/RDataFactory.java

...ime/src/com/oracle/truffle/r/runtime/data/RDataFrame.java

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

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