Fixed: ignore cache when eslint rules have changed

[peternewnham]

I appear to have borked my previous branch after rebasing and it was easier to create a new one from master than figure out what I did wrong :)

This is a fix for #124 and the approach is as follows:

• Get a lint rules object for each CLIEngine instance (using CLIEngine.getConfigForFile)
  • This is taken from the rules of the first file to be processed for each engine (I assume every file processed by the same engine will share the same lint rules)
• Hash the rules object
• Include the hashed rule in the cache against each file so it can also be compared when deciding whether to use the cache

[viankakrisna]

any update on this? need this to make facebook/create-react-app#1578 possible :)

[MoOx]

We should adjust the PR with the new test runner used. @wrakky Can you take care of this?

[peternewnham]

Oops I thought I did that already. Should be sorted now :)

[MoOx]

Released as 1.6.3

[xtroncode]

I am facing this issue in ^3.0.2 for eslint-loader, looking at the latest code, it does not seem to consider the rules hash @MoOx @wrakky
sorry there is already an open issue #214