The codebase was incredibly inconsistent with the use of spacing around
curly braces, e.g.:
```
// this?
const a = {b: 1}
// or?
const a = { b: 1 }
```
This extended into import statements also. Google's styleguide is no
spacing, so we're going with that.
This patch:
- introduces ExecutionContext class that incapsulates javascript
execution context. An examples of execution contexts are workers and
frames
- introduces JSHandle that holds a references to the javascript
object in ExecutionContext
- inherits ElementHandle from JSHandle
Fixes#382.
This patch refactors doclint so that more checks and more generators
could be added.
This patch:
- Introduces 'Source' class, which holds file content in-memory and
allows it to be updated.
- Introduces 'Message' class - which is a pair of a text and a type.
Messages could have either 'error' type or 'warning' type.
