Docs: clarity re: purpose of viewerXOffset
Formatting: remove old code

This was the method of updating the toolbar before the current Events-based way.
Fixed: unused hash parameters/state properties

The hash parameters/state properties for height and width are now unused, as they've been superseded by centering the view given in the hash parameters/state.

Refs #151
Fixed: resizeViewer unused

Feature superseded by communicating views via centered offsets, as opposed to sending y offset from top and height.

Refs #151
New: verticalOffset calculated from center of page

Within the getState() function (used for getting a shareable link) and gotoPage function (called upon document load), verticalOffset is now calculated from the center of the relevant page. This sufficiently allows a view of a page to be easily communicated across browsers without having to resize the receiving user's document viewer.

Fixes #151
Formatting: JSHint guidelines (scope, semicolons)
Tests: removed superseded features

The resizeViewer() function and width/height hash parameters are no longer used, as they were previously only in place to communicate a page view across document viewer instances, which has been fixed by changing how verticalOffset is calculated.

Refs #151