Add Rocker style pre-encoding for JStachio

[agentgt]

@jknack I have updated the JStachio module so that it can take advantage of pre-encoding (the static parts of the template are generated as bytes[] in advance).

The reason I did this is that in the techempower benchmarks Rocker performed better than JStachio's naive String.getBytes().

I also have added threadlocal buffering and removed setting charset.

Setting the charset was a bad idea anyway as JStachio unlike others cannot always re-read the template from the filesystem furthermore escaping is naturally tied to charset.

I noticed that Rocker just assumes MediaType.html (and thus UTF-8) so I have done likewise.

I just released jstachio 0.17.0 but it will take an hour or so before central shows it.

[jknack]

@agentgt did you see the Guice release?

We should pick 7.0.0 right?

[agentgt]

@agentgt did you see the Guice release?

We should pick 7.0.0 right?

I assume you mean the DI framework. Yes I think so.

[agentgt]

@jknack

Here are the benchmarking results for JStachio to hopefully prove it as an OK replacement for Rocker in the TechEmpower benchmarks.

https://github.com/agentgt/template-benchmark/blob/utf8/README.md

I also ran the techempower benchmarks with older Jooby and backport of JStachio module and got similar results albeit the difference not as noticeable.

[jknack]

@agentgt you need to rebase

[agentgt]

@jknack I will tomorrow morning. I just noticed the conflict. Sorry about that.