Decimal point improvement

[raplin]

Doesn't handle decimal point very well; it occupies a whole 7-segment try this (which adds the decimal point to the previous digit):

     def write_to_buffer(self, s):
        inPos=0
        outPos=7
        while inPos<len(s) and outPos>=0:
            c=s[inPos]
            inPos+=1
            if c=='.' and outPos<7:
                self.buffer[outPos+1]|=0x80
                continue
            self.buffer[outPos] = self.decode_char(c)
            outPos-=1