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 (Examining Data): Document the 'explore'
command.
* 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 on C constructs.
* testsuite/gdb.python/py-explore.cc: C++ program used for testing
the new 'explore' command on C++ constructs.
* testsuite/gdb-python/py-explore.exp: Tests for the new 'explore'
command on C constructs.
* testsuite/gdb-python/py-explore-cc.exp: Tests for the new
'explore' command on C++ constructs.
