chore: Introduce prettier-eslint and upgrade eslint related packages

[chinesedfan]

Enhanced from #875.

• Introduced prettier-eslint.
• Upgraded to eslint@5 and related packages. Notice eslint-import-resolver-babel-module requires babel@7, so it and its peer dependency babel-plugin-module-resolver are kept the same.
• In order to not change too many codes, prettier is locked too. And some eslint rules are updated or turned off temporarily.
• .eslintrc is replaced by .eslintrc.js as it is recommended to deprecate the non-extension configuration file.

Tips,

• Double asterisks are only useful in Bash >=4 with globstar option on.

[coveralls]

Coverage remained the same at 48.688% when pulling b370d14 on chinesedfan:prettier-eslint into a2aa221 on gitpoint:master.