seek support for connections (limited)

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

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

...cle/truffle/r/nodes/builtin/base/ConnectionFunctions.java

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

.../com/oracle/truffle/r/runtime/conn/ConnectionSupport.java

...rc/com/oracle/truffle/r/runtime/conn/FileConnections.java

...rc/com/oracle/truffle/r/runtime/conn/GZIPConnections.java

...me/src/com/oracle/truffle/r/runtime/conn/RConnection.java

.../com/oracle/truffle/r/runtime/conn/SocketConnections.java

...src/com/oracle/truffle/r/runtime/conn/StdConnections.java

...rc/com/oracle/truffle/r/runtime/conn/TextConnections.java