Added the concept of a Read-Eval-Print-Loop to LLDB.
A REPL takes over the command line and typically treats input as source code.
REPLs can also do code completion. The REPL class allows its subclasses to
implement the language-specific functionality without having to know about the
Also added a PluginManager-based way of getting to a REPL given a language and
Also brought in some utility code and expression options that are useful for
REPLs, such as line offsets for expressions, ANSI terminal coloring of errors,
and a few IOHandler convenience functions.