Parse and visit defdata forms.
Emit defdata forms.
Move file handling into sybilant.compiler namespace.
Emit defdata forms in a separate section.
Allow a symbol for displacement of a memory reference.
Remove unnecessary let variable.
Fix bug in visitor when a node is nil.
Fix emitting defdata.

Only allow parsing ints and uints.

Emit data with pseudo-instructions.
Update roadmap.
Bump to 0.3.0.