Add base development environment

This changeset adds the beginnings of a development environment for the
project. See the `README` for details.
Merge pull request #1 from azavea/feature/hmc/local-dev

Add base development environment
Add missing nyc-trees roles

The original `.gitignore` for Ansible roles was too aggressive and
prevented roles not pulled in from Ansible Galaxy from being committed.
This changeset adjusts the `.gitignore` and adds the missing `nyc-trees`
roles.

Resolves: #2
Add error message when ansible-galaxy command fails

If anything went wrong with the `ansible-galaxy` command, things were
failing silently. This changeset detects any failures and bubbles them
up to the user in an error message.

Partially resolves: #4
Update Ansible version requirement in README (1.6+)
Add `pre_tasks` for updating the APT cache

In order to prevent inconsistencies with package versions, try to start
provisioning with a fresh APT cache.
Bump azavea.relp to 0.1.1

See: https://github.com/azavea/ansible-relp/pull/2
Merge pull request #7 from azavea/hmc/bump-relp

Bump azavea.relp to 0.1.1
Merge pull request #8 from azavea/hmc/warm-apt-cache

Add `pre_tasks` for updating the APT cache
Add timeouts to ansible provisioning.

Fixes #12
Merge pull request #13 from maurizi/fix-ansible-provisioning

Add timeouts to ansible provisioning.
Add support for Graphite/Statsite

This changeset adds support for three different metrics collection
tools:

- Collectd

Collectd is a lightweight system metrics (disk, memory, CPU) collection
agent.

- Graphite

Graphite is made up of several things, but in general it is a
time-series data store with dynamic graph generation capabilities.

- Statsite

Statsite is an implementation of StatsD in C. It aggregates incoming
statistics and flushes them to a backend time-series data store
(Graphite in this case).

All of these things are being added to the environment in order to
accomplish something like this:

http://codeascraft.com/2011/02/15/measure-anything-measure-everything/

In order to view the Graphite Web UI, navigate to
`http://localhost:8082` on the VM host. Also, standby for @jwalgran to
determine what client will be used to feed Statsite/Graphite from
Python.
Initial proof-of-concept of browserify + factor bundle
Add bundle minification + sourcemaps
Don't minify when passed --debug
Fast rebuilding of bundles using watchify
Add versioning of files based on their contents.

Renames file to include a portion of their md5sum in their filename.

e.g. home.js -> home.88d85647.js
Creates a rev-manifest.json with the mappings of old to new filenames
Add task for compiling sass files into CSS.

gulp-rev-all will version css and image files as well, and rename urls
inside the generated CSS files to point to the versioned images
Add concatenation, minification and versioning of vendor CSS files
Use a livereload server when using gulp watch