Merge pull request #27 from kcwu/fix-strgrow

Fix potential heap buffer corruption due to Strgrow
Strupper(Str s)
{
    int i;
    STR_LENGTH_CHECK(s);
    for (i = 0; i < s->length; i++)
	s->ptr[i] = TOUPPER(s->ptr[i]);
}

Strupper(Str s)
{
    int i;
    STR_LENGTH_CHECK(s);
    for (i = 0; i < s->length; i++)
	s->ptr[i] = TOUPPER(s->ptr[i]);
}
