* support for closing and re-opening the devices including the windowed AWT based device

Restructured code in GrepFunctions to use cast pipeline for argument checking.

Fix: Package 'jsonlite' expected CHAR(x) to return the same pointer on subsequent calls if x is the same. Now, strings are cached.

Added class NativeConnections represented such connections and performing native calls for reading and writing.
This changes make package "curl" working.