Update Plotly link to Plotly's new user guide
Merge pull request #270 from chriddyp/master

Update Plotly link to Plotly's new user guide
don't add trailing slash after url params
fix word matches in transform_ipynb_uri

`\w` is never the right pattern, use `[\w-]`
fix url_rewrite_dict ordering

it was an OrderedDict created from a regular unordered dict,
defeating the purpose and making a random order.
handle GitHub tree urls
skip github blob redirect test

While we figure out the right fix.

The underlying GitHub redirect we relied upon no longer happens.
Merge pull request #274 from minrk/backslash-w-minus

fix word matches in transform_ipynb_uri
Merge pull request #273 from minrk/add-slash

don't add trailing slash after url params
handle truncated gists

Needed for gists larger than 1MB

gists larger than 10MB will get 403 from the raw request.
I don't see a way to get these, for now.
Merge pull request #278 from minrk/gist-raw

handle truncated gists
use GitHub blobs API

instead of raw.githubusercontent

at the request of GitHub support.

This also fixes the blob->tree redirect, so that test is unskilled.

Still some testing to do before merge.
Merge pull request #281 from minrk/blob-api

use GitHub blobs API
apt-get update on travis

failing with 404 on libcurl4-gnutls-dev
remove unused flake8 dev-requirement
cache Content-Type headers

cached content is currently being served as 'text/html'
Use GitHub auth when fetching blob API

add GitHubClient.fetch, which adds GitHub auth to a regular fetch
fix typo in github token auth

key is `access_token`, not `token`, so anyone using GITHUB_API_TOKEN would not actually get authenticated requests
forward url parameters on /url[s] requests upstream

closes #286
remove `?create=1`

This was added as a way to detect whether links come from the front page. It’s no longer necessary because we have an explicit list of those URLs in frontpage.json

also makes the path to frontpage.json configurable,
because why not?