prosody-volume and prosody-rate as numbers&relative changes as well as labels about unimrcp HOT 5 CLOSED

I have made the changes for prosody rate and volume.

w3c ssml says

prosody-rate can be either a relative change or a label. and relative change for rate
is a number and number is a simple positive floating point value without
exponentials. but relative change of volume is a number preceded by "+" or "-".

prosody-volume can be either a numeric value, which is a number, a relative change,
which is a number preceded by "+" or "-", or a label.

I am pretty sure I did everything right about rate_parse and volume_parse functions,
but I am not sure about generate functions.

Please check and feel free to offer any corrections.

See what a "number" means http://www.w3.org/TR/speech-synthesis/#number_values
See what a "relative change" means http://www.w3.org/TR/speech-synthesis/#relative_values

Thanks. I'll look into this hopefully tonight.

I've just committed your modifications to trunk (r843).

I made only a few modifications over your version (just some minor formatting
changes). Overall it looks exactly the way I expected. I tested both parse and
generation and both just work for all of the cases.
The only concern what the default case should be in if -> else if -> else chain in
parser and generator routine. Should we have else (default) case at all? Anyway this
is not going to be an issue just some thoughts.

BTW, I mainly tested it with tester application (tests/mrcptest). There are v1 and
v2
test messages. You can easily put any message in v1 or v2 dir and run mrcptest to
process (parse -> generate).