[GR-2733] Fix escaping/quoting of string printing and various printing cleanups.

.../com/oracle/truffle/r/nodes/builtin/RBuiltinPackages.java

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

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

...cle/truffle/r/nodes/builtin/base/printer/ListPrinter.java

...truffle/r/nodes/builtin/base/printer/PairListPrinter.java

...truffle/r/nodes/builtin/base/printer/PrintParameters.java

...fle/r/nodes/builtin/base/printer/StringVectorPrinter.java

...om/oracle/truffle/r/nodes/builtin/base/printer/Utils.java

...es/src/com/oracle/truffle/r/nodes/unary/ToStringNode.java

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

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

...cle/truffle/r/test/builtins/TestBuiltin_printdefault.java