Fix tushare plot and China A Share Market Demo

[Yuchen-Song]

Fixed tushare plot_all(), and plot() method with specialized baseline, Updated demo files with available trade time span

[zhumingpassional]

thanks for your codes. have you tested it?

[Yuchen-Song]

thanks for your codes. have you tested it?

Yes, I have tested them. Please refer to these two github gists for more information. FinRL-Meta/tutorials/1-Introduction/China_A_share_market_tushare.ipynb FinRL-Meta/tutorials/3-Practical/FinRL_China_A_Share_Market.ipynb