Add JSHint and JSCS linting to the build process

[tehapo]

A lot of lines were touched in this pull request. 💦 Still there are no actual code logic changes, except a repeated test data creation pattern was simplified to avoid warnings about creating functions inside a loop.

I self-reviewed all the changes after automated find and replaces and verified manually that all demos still work.

PS. I'll just leave this Kekkonen reference here also. 😆

[manolo]

A lot of chantes here, I have not gone over them, so, can you explain what are the things we should focus to review?
Also how did you formatted all those files? are there new gulp tasks ?

[tehapo]

(By the way, if you feel like this is too big of a change, we can abandon this with no hard feelings from me and revisit the linting later after smoke has cleared from the 1.0 release.)

The vast majority of changes are simply changing quotation marks (") to single quotes (') as required by the google preset configured in JSCS. Also adding missing spaces and semicolons was a big part of the change.

I think the only focus for this review should be that there are no accidental code changes, except the test data generation in some examples, which I already mentioned. Configuration of the linters is basically just copied from vaadin/vaadin-combo-box with the addition of allowed (non-standard) JSDoc annotations required by the Grid docs (see .jscsrc file).

The formatting changes were done manually (and with find and replace feature) after first running the new gulp lint:js and gulp lint:html tasks to find out what lines are still conflicting with the style guides.

[manolo]

Reviewed 35 of 40 files at r1, 4 of 5 files at r2.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from the review on Reviewable.io