I noticed that the image that accompanies auto-completion suggestions
when the tern addon is active gets cut slightly, because the default
line height is slightly smaller than the image height.

This change above ensures that the line height is bigger, hence
ensuring that the image is fully shown.

Issue #3369

Was a little subdued

Closes #3365

Spent quite a while perfecting this (IMO), but a lot of people seem to
really like it. Hope you do too.

See http://discuss.codemirror.net/t/tern-special-characters-causing-issues/294

Issue #3362

Closes #3361

Closes #3348

Closes #3336

So that selection inside widgets isn't affected

Issue #3342

Closes #3345

Issue #3346

Closes #3340

Closes #3339

And add a styleDefs option to turn it off.

Issue #3332

Issue #3332

So that they don't end up overriding more specific styles.

Issue #3325

Issue #3325

Closes #3322

Issue #3321

Issue #3316

This PR initialize docs before creating tern server instance, because
in some case, tern server creation call getFile which use docs.

I have this case by using requirejs tern plugin + custom plugin which
defines modules :

```json
{
    "!name": "delite",
    "!define": {
      "!requirejs": {
        "delite/register": {
          "!type": "fn(tag: string, superclasses: [], props: ?) -> fn()",
      }
    }
  }
```

Issue #3320