the RangeEnabled option now has no effect, but it still exists in the API. A few
tests still use it to ensure this. This would only be considered a breaking
change if someone was relying on Pilosa to enforce the RangeEnabled: false
option to prevent fields being created in certain frames. This seems unlikely.
these were occaisionally referenced elsewhere in the codebase - in all but one
case, there were workarounds that are actually better I think.
In the one case there wasn't I created a single top level DefaultConfig object
which is instantiated with all the default values and can be referred to if
necessary.
There was a bug in fragment.go with the way MaxWritesPerRequest was treated if
it was 0. Elsewhere, 0 meant no limit, but here, it would have caused a division
by 0.
Changed the default metrics provider from "nop" to "none", although "nop" will
still work. Previously, any value other than "statsd" or "expvar" was treated as
"nop", but I've changed this behavior to return an error if an invalid string is
provided. I think this is better behavior, because in the case that someone
bothered to change the default, they were probably interested in actually
getting stats, and might be annoyed when it silently failed.
