Backends: Move internal datastructures into package.
Backends: Simplify some internal naming.
Query: First draft of graphite-compatible query engine.

The parser is built using the Ragel parser-generator, so that will be
needed in case any changes has to be made to the actual parser.
Makefile: gofmt ragel output.
Parser test: Build better example data.
Parser: Remove the initial toy parser.
Query: Use new backends-helpers.
Query: move things around a bit.
Query: Major code reorg.
Query: Convert nodes to AST.
Query: Implement getting actual data out.
Query: Hoist internals into Query package.
graphiteParser: Fix package name.
Query: Don't import graphiteParser into namespace.
Query: Return errors when query execution goes wrong.