This patch takes care of the lowering of events/coordinates arrays as
path data, which originates from a `commands: ...` string of SVG path
commands.
In order to minimize the path specific code in the generator, the
compile_paths now generates a Vec<Expression> for the events and
coordinates.
A `Path` with `MoveTo`/`LineTo`/etc. sub-elements now maps to an Expression::PathData of type
Type::PathData.
The llr lowering creates an Array of Type::PathElement, which is casted to PathData.
This only covers the element case. The compiled path events are still todo.
Use only specific lyon packages instead of pulling all of them in.
This slightly speeds up compilation as well as for example lyon_tesselation
doesn't need to be compiled anymore.
* Always apply a transformation (less variants)
* Let the path data iterator take ownership of the data. That will
make it possible to return a PathDataIterator from a function in the
future
