Improve and simplify production and mixin parsing; other tweaks;

Author: Tom

README.md

@@ -11,7 +11,7 @@ It renders L-Systems via the *turtle graphic* technique to create procedurally g
 | Property               | Description                                                                                           | Default Value |
 | ---------------------- | ----------------------------------------------------------------------------------------------------- | -------       |
 | axiom                  | (string) Initiator/initial string/axiom.                                                              | `'F'`           |
-| productions             | (string) Productions `from`:`to`. Separate by space. eg: `productions: F:FF X:F+X+F`                                                    | `'F:F'`       |
+| productions             | (string) Productions `from`:`to`. Separate by acomma. eg: `productions: F:FF, X:F+X+F`                                                    | `'F:F'`       |
 | iterations             | (int) How many times the productions should be applied                                                         | `1`          |
 | angle                  | (number) Degree change to apply for rotation symbols like, `+`, `-`, `>`, `<` etc.                                           | `45.0`        |
 | segmentMixins          | (list) For any symbol you want to be rendered, you need to assign them [mixins](https://aframe.io/docs/0.3.0/core/mixins.html) here. Let's say you want F and X to be rendered, then you could write `segmentMixins: F:blue line X:big sphere`. You may define multiple mixins per symbol if you plan to use `!` and `'` in your L-System to increment/decrement the mixin index, which directly relates to your *segmentMixins*. Eg. `F: red line,blue line,green line` with an Axiom `F!F!F` will produce exactly three lines with those colors. Be sure though to actually define mixins you want to use in you assets. Take a look at some of the examples to get a better idea how this works, eg. the [multi-mixin example](https://github.com/nylki/aframe-lsystem-component/blob/master/examples/multiple%20mixins/index.html).  |         |