Add a JacksonMatcherFilter.

This new module and class combines the jackson json filter with a Matcher to output only the json that is requested.

Fixes #4
Make it easier to use partial response with jackson+jaxrs.

This adds a new utility to the jackson module: JacksonFilters - which can be used to configure an ObjectMapper to filter based on a partial response pattern.

I've also added a new module that adds jax-rs specific code to interact with the jackson-jaxrs module, providing a ContextResolver for ObjectMapper that looks for a request parameter and automatically applies the partial response filter for you.

Fixes #5
com.pa.fire.partialresponse.fields -> com.pa.pr

IDE refactor to move classes from com.pressassociation.fire.partialresponse.fields to com.pressassociation.pr
Add README.md for the jackson json filter project with examples.
Rename the fields-parser module to matcher.
Change parent pom name.