Improve the README guide for windows users and add more content [#14]

+ Add note for windows user to restart computer after installing vagrant
+ Add slow internet connection section to use download accelerator to download .box file first
Improve the README guide for windows users and add more content [#14]

Add *Join and work with us?* section
Improve the README guide for windows users and add more content: Add FAQ for Windows support [#14]
Improve the README guide for windows users and add more content: Add more note for Windows, FAQ [#14]
Merge remote-tracking branch 'hoatle/enhance_14_README' into develop