This commit makes a number of performance improvements to
reduce allocations during query execution. Several objects
and buffers are now reused across the components to avoid
allocations.
Previously a simple `count(value)` query across 1M points
would require 26,000+ allocations. After the changes in
this commit that number has been reduced to 88.
Since we are pinned to go 1.4.3, we're using the same dependency
manager as telegraf to make builds more reproducible. We'll re-evaluate
vendoring when we can move off of 1.4.3.