转http://www.cnblogs.com/darkknightzh/p/6117528.html
参考网址:
http://stackoverflow.com/questions/22408237/named-colors-in-matplotlib
http://stackoverflow.com/questions/8409095/matplotlib-set-markers-for-individual-points-on-a-line
https://matplotlib.org/gallery/index.html#subplots-axes-and-figures