New color system

[afc163]

1. Brand new color palattes!
2. Brand new color algorithm replacing the tint/shade system.
3. Change default font color.

After Using js functions inside less code, now we make the color style code is extremely complex... 😓

[mention-bot]

@afc163, thanks for your PR! By analyzing the history of the files in this pull request, we identified @zhujun24, @benjycui and @sliuqin to be potential reviewers.

[coveralls]

Coverage remained the same at 71.523% when pulling 5be075a on new-color-system into c3982b0 on master.

[yesmeck]

make sure no one can understand it