h5edit

New Feature: adding MODIFY command.

Initial version check in. More work is needed.
Tests passed in Jam, Koala, Ostrich, Emu, Duck, Wren, Platypus.

RENAME is failing and its tested are temporay skipped in testh5edit.sh.

src/modify_cmd.c:
    new source module to hand the MODIFY command.

src/Makefile.am:
src/Makefile.in:
    addition of modify_cmd.c source module to support the MODIFY command.

test/testh5edit.sh:
    Added MODIFY command tests.
    (RENAME commands are failing. Skipped them temporary.)

src/analyze.c:
src/analyze.l:
    Added MODIFY keyword.

src/parse.y:
src/parse.c:
src/parse.h:
src/h5edit.h:
src/misc.c:
    Revamp the structure to support MODIFY command.

src/main.c:
    Changed h5edit_command to a const variable to eliminate compiler warning on this.

src/create_cmd.c:
    Modified to use the new structure.