* Network: Add extra check on null value during label handling

This fixes an oversight in #3486. Unit tests added, not only for null labels, but for all weird label values I could thing of.

* Enhanced unit tests, adjusted label check

* The next fix on Travis unit test failure

This is the next escalation on the war against the Travis unit tests failing (which came into being by yours truly).
By accident, I could recreate the unit test failure on my development machine. This led to a more directed effort to
squash the bug.

The insight here is that test `(window === undefined)` fails, but `(typeof window === 'undefined`)` succeeds. This undoubtedly has to do with the special status `window` has as a global object.

Changes:

- Added check on presence of `window` in `Canvas._requestNextFrame()`, fixed local source errors.
- Added catch clause in `CanvasRendered._determinePixelRatio()`
- small fix: raised timeout for the network `worldCup2014` unit test

* Preliminary refactoring in utils.js

* Added unit tests for extend routines, commenting and small fixes

* More unit tests for extend routines

* - Completed unit tests for extend routines in
- Small fixes and cleanup in `util.js`
- Removed `util.protoExtend()`, not used anywhere

* Added unit tests for known font options

* Interim save before trying out another proto chain strategy

* Fixed problem in first example #3408

* Removed silly file that shouldn't be there

* Added unit test for multi-fonts

* Comment edits

* Verufy unit tests, small adjustments for groups

* Further work on getting unit tests to work. PARTS NEED TO BE CLEANED UP!

* Further tweaks to get unit tests working

* All unit tests passing

* Fixes due to linting

* Small edits

* Removed prototype handling from font pile

* Fixes during testing examples of #3408

* Added unit test for edge labels, small fixes

* Added unit tests for shorthand string fonts; some tests still failing

* All unit tests pass

* Removed Label.parseOptions()

* Completed shorthand font tests, code cleanup, fixed choosify for edges

* Addressed review comments

* Addressed review comments, cleanup

* Refactoring of label splitting; new unit test still failing.

* Label acc size calculations to separate methods.

* Final fixes and cleanup