stylelint caching

[woble]

Stylelint added caching in 7.10.0 (Ref: stylelint/stylelint#2293). Can it be enabled through gulp-stylelint?

[olegskl]

Hello. Unfortunately, the tests do not pass with 7.10.1. This is probably a bug in stylelint.

[olegskl]

Not planning to use stylelint's caching. Caching should be done on gulp level.

[ZhangChengLin]

#127