The PQL looks like:
```
Range(frame=f, field0 >< [200,610])
```
One thing I noticed while implementing this is that it doesn't seem
like `FieldRange()` is used in either `Frame` or `View`; the Executor
calls `Fragment.FieldRange()` directly. The problem with this is that
the offset logic is calculated in the Frame, but since the Executor
doesn't go through Frame, then the Executor also has to calculate
the offset before calling `Fragment.FieldRange`. We should unify this
logic somewhere. Note, this applies to both `FieldRange` and
`FieldRangeBetween`.
this affects the scanner/parser and makes it produce signed ints rather than
uints, and so it affects all code that is expecting unsighed ints to come out of
the parser.
Consolidates all the pql.Call implementations into a single
pql.Call struct. This is needed to support user-defined schemas
on frames.
This also has the added benefit that a lot of redundant parsing
code has been consolidated.
This commit refactors the pilosa codebase. It makes several major
changes:
* Removes bitmap handles
* Removes dispatch/hold/transport
* Removes etcd dependency
* Adds consistent hash ring for slice placement
* Refactors parser/lexer
* Adds strong typing to PQL AST
* Flattens package hierarchy
