This is the implementation of the 'explore' command in Python.

2012-03-05 Siva Chandra <sivachandra@google.com>

        New command 'explore' which helps explore values and types in
        scope.
        * NEWS: Add an entry about the new 'explore' command.
        * data-directory/Makefile.in: Add gdb/command/explore.py
        * python/lib/gdb/command/explore.py: Implemention of the 'explore'
        command using the GDB Python API.
        * doc/gdb.texinfo: Add description about the 'explore'
        command in the chapter 'Examining Data'
        * testsuite/gdb.python/Makefile.in: Add py-explore to EXECUTABLES
        * testsuite/gdb.python/py-explore.c: C program used for testing
        the new 'explore' command.
        * testsuite/gdb-python/py-explore.exp: Tests for the new 'explore'
        command.