Refactor the svg compiling into a factory

The compiling functionality could ideally be used by other custom SVG directives. I separated the functionality that handles compiling of an element into a factory that other directives can inject for reuse.
Updated factory name

Changed factory name to be more descriptive - svgBuilder to svgCompile.
Merge pull request #1 from rezen/patch-1

Refactor the svg compiling into a factory