Previously, `xLine`, `xLineTo`, `yLine` and `yLineTo` used positional arguments. Now:
- `xLineTo` and `yLineTo` have been removed
- `xLine` and `yLine` both use keyword arguments:
- `length`, optional (i.e. a relative distance along the X or Y axis)
- `endAbsolute` optional (i.e. an absolute point along the X or Y axis)
- `tag` optional
- Exactly one of `length` or `endAbsolute` must be given. Not both, not neither.
For example:
```
// Old way
|> xLine(6.04, %)
|> yLineTo(20, %, $base)
// New way
|> xLine(length = 6.04)
|> yLine(endAbsolute = 20, tag = $base)
```
This also improves some of the general-purpose keyword arguments code in modeling app's TS codebase.
