Document the framework's model transformation APIs

We have a placeholder page for this:
http://wiki.fluidproject.org/display/docs/Model+Transformation

We need to include (not exhaustive):

• transforms now in "fluid.transforms" namespace
• many new transforms available (see ModelTransformationTransforms.js)
• transforms now specified with "transform:" instead of "expander:"
• only supporting 'input' and 'inputPaths' instead of value in the expanders
• Several new transform functions
• "standardTransformation" -> standardTransformFunction