Consume roles as roles, not mixins:

When we consume roles in a single command, we can check for
conflicts. When we load them one at a time, methods will be
overridden between roles.

This is much safer.

Thanks, Ovid! :)
Merge branch 'fix/no-mixins-behavior'
Test demonstrates a case where with_return is not cleared
Catch errors thrown by an apps template engine.

Rendering a error template using an apps template engine may fail. As
state. While state management still needs further cleaning up, we can
catch errors from rendering an error template, and fall back to static
pages if such an event occurs.
reflect changes
Merge branch 'bugfix/catch_error_template_render_errors'
Cleanup docs for route matching.

Documents:
  - mixing of named (token) matching and wildcard matching. Moved (and
    corrected) route chaining example. (Ref: #729)
  - megasplat (**) as part of wildcard matching (duplicate content from
    splat keyword).
  - Note support for named capture groups in section about regex routes.
reflect change
Merge branch 'docs/route_params_and_splats'
Update test skeleton to use to_app
Change test skeleton to OO style Plack::Test
spacing
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Merge branch 'pr/update_test_skeleton_to_app'
Reworked tests to use Plack::Test
Reworked test to use Plack::Test
Added test for returned content
Deleted t/server_standalone based on #636
Changed Dancer2->runner->psgi_app to Dancer2->psgi_app
reflect change