Update VoxForge Tutorial and How-to Julian grammar files with looping on digits

[kmaclean]

Update VoxForge Tutorial and How-to Julian grammar files with looping on digits sample.grammar

S : NS_B SENT NS_E
SENT: CALL_V NAME_N NOISE
SENT: DIAL_V WORD_LOOP
WORD_LOOP: WORD_LOOP DIGIT 
WORD_LOOP: DIGIT NOISE

sample.voca

% NS_B
<s>        sil

% NS_E
</s>        sil

% CALL_V
PHONE        f ow n
CALL        k ao l

% DIAL_V
DIAL        d ay ax l

% NAME_N
STEVE        s t iy v
YOUNG        y ah ng

% DIGIT
FIVE        f ay v
FOUR       f ao r
NINE        n ay n
EIGHT        ey t
OH        ow
ONE        w ah n
SEVEN        s eh v ih n
SIX        s ih k s
THREE        th r iy
TWO        t uw
ZERO    z ih r ow

% NOISE
<sp>    sp

this would create a grammar that is equivalent to the HTK tutorial grammar:

$digit= ONE | TWO | THREE | FOUR | FIVE | SIX | SEVEN | EIGHT | NINE | OH | ZERO;
$name = [ STEVE ] YOUNG;
( SENT-START (DIAL<$digit> | (PHONE|CALL) $name) SENT-END )