Feature/named image transform/multi transform

Addresses #351 

Support chaining of namedTransforms..

`/content/ira.png.transform/hero/small/image.png`

Where `hero` is a NamedTransform with ImageTransforms
```
resize:width=100
greyscale:greyscale:true
```

and `small` is a NamedTransform w ImageTransforms
```
resize:width=50
```

The combined transformation would result in:
```
resize:width=50
greyscale:greyscale:true
```

`LinkedHashMap.putAll(...)` is used to merge the subsequent into the previous, meaning the any prior order is maintained.

A key use case if for "adaptive"-style image definitions ... `/content/ira.png.transform/hero/small/image.png`