Fix problem when determing path of project_root

Fix problem that path of project-root will change by
where user executing script.
Update gitignore
Add feature of checking log dir is exist, and mkdir if false
Add function to log simulation record
Fix problem of comparing two floating number

Change comparing method from "==" to IsFloatEqual(x, y) which proposed by Knuth.
Add ignore rule for plot_data
Add some scripts to plot simulation record
Merge branch 'testing' of https://github.com/ChuKuanYu/BTTE into testing