Unified CRFFI for LLVM and NFI

...oracle/truffle/r/ffi/impl/common/JavaUpCallsRFFIImpl.java

.../src/com/oracle/truffle/r/ffi/impl/interop/DLLInfoMR.java

...fle/r/ffi/impl/interop/FFI_RForeignAccessFactoryImpl.java

...src/com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_C.java

.../com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Call.java

.../truffle/r/ffi/impl/llvm/TruffleLLVM_UpCallsRFFIImpl.java

...rc/com/oracle/truffle/r/ffi/impl/nfi/TruffleNFI_Call.java

...le/truffle/r/ffi/impl/nfi/TruffleNFI_UpCallsRFFIImpl.java

.../src/com/oracle/truffle/r/ffi/processor/FFIProcessor.java

...c/com/oracle/truffle/r/runtime/data/CharSXPWrapperMR.java

...c/com/oracle/truffle/r/runtime/data/NativeDataAccess.java

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

...r.runtime/src/com/oracle/truffle/r/runtime/ffi/CRFFI.java

...e.r.runtime/src/com/oracle/truffle/r/runtime/ffi/DLL.java

...e/src/com/oracle/truffle/r/runtime/ffi/FFIUnwrapNode.java

...ime/src/com/oracle/truffle/r/runtime/ffi/FFIWrapNode.java

...rc/com/oracle/truffle/r/runtime/ffi/UnwrapVectorNode.java

...c/com/oracle/truffle/r/runtime/ffi/VectorRFFIWrapper.java

.../src/com/oracle/truffle/r/runtime/ffi/WrapVectorNode.java