Add InfluxQL scanner.

This commit adds a pure Go implementation of the InfluxQL scanner. It includes support for:

- Identifiers
- Numbers
- Strings
- Durations
- Booleans
- Numeric and logical operators
- InfluxQL keywords
Merge branch 'master' of https://github.com/influxdb/influxdb into scanner
CHANGELOG
Fix EQ token scanning.
Add instructions on how to set branch and commit hash
Fix Scanner.Scan() comment.
Add semicolon, INSERT, INTO to Scanner.
Merge pull request #1151 from influxdb/scanner

Scanner
Open the Server
Add influxql parser.
Add LIST/DROP SERIES and LIST/DROP CONTINUOUS QUERIES.
Merge pull request #1153 from influxdb/add_versioning

Add instructions on how to set branch and commit hash
Merge pull request #1158 from otoolep/bringup

Open the Server object
Revert "Merge pull request #1158 from otoolep/bringup"

This reverts commit 081be7a0bcd8eeb07b489877c1b098543ae01a55, reversing
changes made to b60e6ecca9275b5a675a7023487b5bdb00350b0a.
Change DROP CONTINUOUS QUERY to use a query name.
Add test for influxql case insensitivity.
Add garbage influxql test.
Add influxql.Call.
Add CREATE CONTINUOUS QUERY parsing.
Add ParenExpr.