* Makes network eslint compliant
Unused variables in private functions, who were never called internally with those arguments were removed.
lint rule was disabled for public functions, and in private functions which were called internally with those unused arguments

* Disables linting for unused args passed into DataSet and DataView

Code in the `_line()` of the sibling Bezier edge types was either extremely similar or identical.
The Bezier drawing code has been consolidated in a single method in the parent class.

This method is needlessly complicated. Code has been adjusted to better show the intent.

In addition:
- reuse of variables already present, notably `dx` and `dy`
- put recurring code fragments into local variables
- removed second conditions in constructs of the form `if (condition) ... else if (!conditioni) ...`

The refactoring can be taken further, but it would change the conditional flow, which would complicate reviewing.
The current changes highlight the similarities between the code blocks.

* self reference edge should now appear in all cases
* add checks for shape width being NaN to get correct circle data
* reorder resize arguments in Diamond, Dot and Star

* element characteristic changes
* assume edge color inheritance is correct before choosing
* Adjust nodes’ chosen’s boolean -> bool
* Need to get user-reset size
* make example edges thicker for more noticeable shadow
* preemptive ES6 fix (see #2500/#2501)
* documentation for the feature that was previously overwritten

Signed-off-by: André Martins <aanm90@gmail.com>

see #1608

- Fixed #1528, #1278, avoided ID's being cast to string for methods that return ID's as well as storePositions casting to string.