Add date autosuggest to readme; Add en-gb support

[liamcain]

solves #18 solves #30

• README changes
• Chrono now looks at the moment.js locale to determine what it should use (only en-us and en-gb supported currently)
• Minor improvements to date autosuggest
  • Added new setting autosuggestLinkToggle instead of relying on the value of modalLinkToggle. This seemed more intuitive to me, but let me know what you think @argenos
  • Only register a CodeMirror event if the autosuggest is enabled
  • properly unregister event when the plugin is disabled/unloaded
  • Fix regex for X days ago so it shows up in the autosuggest again
• I added eslint to catch all the Typescript warnings. For a smaller diff, don't look at the last commit.

[liamcain]

Updated. Any opinion on this comment?

Added new setting autosuggestLinkToggle instead of relying on the value of modalLinkToggle. This seemed more intuitive to me, but let me know what you think @argenos

(Previously the behavior was to keep autosuggest in sync with the datepicker settings.)

[argenos]

I agree! I think it makes sense to separate these two contexts. Ready to merge?

[liamcain]

Yep, feel free to merge!