完成複數根在復平面坐標系的plot程序部分， 測試驗證通過。
Add the .gitignore file for current, to record the git-ignore list.
Slightly modify the .gitignore  --->  *.m~    Just ignore the temporary backup .m file.
添加兩個m程序文件 ： Attenuation_oscilating_curve.m    and    Complex_number_matrix.m

Complex_number_matrix.m  ===>  計算複數矩陣
Attenuation_oscillating_curve.m ====> 用來畫出衰減振蕩曲線
Merge pull request #2 from xu-zan/develop

Agreed to merge branch 'develop' into 'master'.  Passed!