h5edit

Added support to allow attribute names consist of "_".

src/analyze.c:
src/analyze.l:
    Parser now accepts "_" as part of identifiers.
src/misc.c:
    Just some debug statements.

test/testfiles/create-newatts-I3264BE.ref:
test/testfiles/create-newatts-F32BE64LE.ref:
test/testfiles/rename-atts12-dset111.ref:
test/testfiles/rename-atts12-grrt.ref:
test/testh5edit.sh:
    Updated test cases to use "_" in the attribute names.

Tested: koala, jam, emu, duck, ostrich.