Rename existing address-normalizer module to osm.

(address-normalizer -> lib/addresses/osm).js
  -Create a `lib/` directory for most javascript source files, for
  more coherent project structure.
  -Create subdir `addresses/` for all address dataset importers.
  -Rename `address-normalizer.js` to `osm.js`.
Redefine addresses() to output a Readable stream.

lib/addresses/osm.js
  -Rename `addresses()` to `addressStream()`.
  -Redefine it to return its normalized/filtered Stream.
  -Add documentation comment.
Move Address() to own module, for reusability.

lib/(address, addresses/osm).js
  -Move the `Address()` constructor from `osm.js` to its own
  module, `address.js`, for reusability in other address modules.
Fix inconsistent parenthesis whitespace.

index.js, lib/addresses/osm.js
  -Add a space after `(` and before `)` where appropriate, for
  style consistency.
Define testImports(), make main entry point.

index.js
  -Define `testImports()`, now the module's main entry point,
  which simulates ultimate usage better than `handleUserInput()`
  (these will be scripted imports after all).

lib/addresses/tiger.js
  -Add a skeleton module for the TIGER importer.
Define filter(), normalizer(), addressStream().

lib/addresses/tiger.js
  -Define `filter()`, a placeholder `normalizer()` for testing
  purposes, and `addressStream()`.
Add interpolate addresses in normalizer().

lib/addresses/tiger.js
  -Define nested function `interpolateAddressRange()`, and use it to
  created interpolated address ranges in `normalizer()`.
Add interpolated address street offsets.

lib/addresses/tiger.js
  -Offset interpolated addresses by a small distance from the road
  centerline, depending on their TIGER designated position.
Update package.json dependencies.

package.json
  -Remove unused dependencies, add used ones.
Merge branch 'feature/tiger-import' into develop

lib/addresses/tiger.js
  -Implement a module for ingesting, normalizing, and interpolating
  addresses in TIGER shapefiles.