introduce express.Router( ), small renaming

Rename a few things here and there to help clarify the situation.

This change introduces use of express.Router( ), which provides the routing
functions of express without the full app.
This also shows an experiment observing the interaction betwen express( ) and
express.Router( ).
There are a few reasons for doing this:

Using express.Router( ) allows introspecting existing routes.
As a REST application, our content payloads should include URLs, links to other
resources available from our API.  As a bonus feature, it's often nice for a
meta page to describe the links, status, and version available from this
particular API.  By far, the easiest way to implement this is to introspect the
existing routes.

Separating the code makes testing easier.
This lays the ground work for breaking apart the code into smaller, more
testable modules.
quick renaming for clarification

This avoids re-using the same variable name in different contexts.
prepping for another re-org

Small hack in order to start separating things out a bit more.
make some breathing room for separate entries
move entries api to separate module

Make as few adjustments as needed to get entries api into it's own module.
quick clean up
preparing to seperate settings and experiments
remove dead code
move experiments and settings to own modules

Also remove notion of common configured middleware.
remove bit of dead code
move all rest components to separate modules
remove api.js in favor of api/ module
let test run
Merge pull request #43 from nightscout/wip/api-modules

Merging @bewest's wip/api-modules branch