Branch tag gdb_7_1-branch added for insight-specific sources

[Kevin Buettner <kevinb at redhat dot com>]

I've tagged the insight-specific sources with the branch tag,
gdb_7_1-branch.  Specifically, I've tagged the following directories:

    gdb/gdbtk
    gdb/testsuite/gdb.gdbtk
    tcl
    tk
    itcl
    libgui

The rest of the GDB sources have already been tagged with
gdb_7_1-branch.  Now that the insight-specific sources have also been
tagged, it is possible to check out insight using this the tag and
obtain a tree from which insight may be built.  I've done a test
check out and build to verify that it can indeed be done.  The version
number displayed by Help->About GDB... is correct.  (I haven't done
any testing beyond this simple smoke test.)

I did not create a branch point tag, but can do so if desired.  (Let
me know within the next few days...)  If a branch point tag is desired,
it should be named gdb_7_1-2010-02-18-branchpoint in order to match
the rest of GDB.  The date won't be quite right, but will be close
enough, and, IMO, it is more important that it match the tag used by
the rest of GDB.

Kevin