Further enhancements to factor and data frame support. Fixed an argument matching bug.

...fle.r.engine/src/com/oracle/truffle/r/engine/REngine.java

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

...ltin/src/com/oracle/truffle/r/nodes/builtin/base/Dim.java

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

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

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

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

...acle/truffle/r/nodes/access/array/write/CoerceVector.java

...fle/r/nodes/access/array/write/UpdateArrayHelperNode.java

.../com/oracle/truffle/r/nodes/function/ArgumentMatcher.java

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

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

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

...acle/truffle/r/runtime/data/model/RAbstractContainer.java

...est/src/com/oracle/truffle/r/test/ExpectedTestOutput.test

...le.r.test/src/com/oracle/truffle/r/test/all/AllTests.java

.../com/oracle/truffle/r/test/simple/TestSimpleBuiltins.java