factory: some API improvements

add a few methods to Factory to ease its usage
core: add source location hint in operation description when generating router

This will allow better trackability, and may allow to provide link to sources in api doc
core: add some non standard status codes
core: review programmatic API to build a router [BREAKING]

- don't provide it on StdRestxMainRouter directly, but on router, so that it can be used in combination with other routers
- provide API for routes consuming data, making necessary to make MatchedEntityRoute accept an input
- ease the creation of StdEntityRoute with a builder
convert SimpleServerExample into an automated test

This is testing both SimpleWebServer basic usage and new programmatic API
minor: rename test class to match class under test name (StdRestxRequestMatcherTest)
core: add support for new path param definitions

When defining a path pattern, you can now:

- use curly braces to delimit the parameter name. eg "/user/{name}"
- use a custom regex to match the path parameter. eg "/user/{name:[A-Z]{1,3}}
- use column based notation, like the one used in AngularJS resources. eg "/user/:name"