using canny edge detection

 - Wire matching uses Canny edge detection.
 - Canny edge detection has good performance than those of Zero crossing edge detection. It can detect outline of wire. But it is necessary to be a single line.
 - low & high hysteresis text bar were added at wire matching menu by using 'glade interface design program'.
 - optimum hysteresis values are 0.07 0.25.(sample project, degate_0.1.0_2011-05-05_1607_legic_prime.zip, in degate.org)