Node 5 is neither latest or LTS. This is not removing support for
Node 5, it's simpky removing it from day-to-day CI for faster builds.

This originally caused issues because sass spec was in the test
folder. As of #1698 sass spec is now an npm devDependency. Without
the test folder published the node-citgm cannot execute our
`npm test`.

These specs would use the local environment for `SASS_BINARY_NAME`.
This means in the local environment wasn't supported these specs
would fail unexpectedly. This doesn't play well with the node-citgm
because these specs would fail anytime the module version was bumped.

Update ISSUE_TEMPLATE with Bootstrap format

Took the basic structure from Bootstrap since they have a large project
that gets a lot of issues
[skip CI]

Replace util._extend with Object.assign

Update spec runner for full sass-spec coverage

Closes #1709

ESLint 3.x updates

This was never part of the public API, and has officially been
depreciated in Node 6 https://github.com/nodejs/node/pull/4903
Object.assign can't be used yet since it requires ES2015

Revert "Publish tests to npm"

This reverts commits
2c2f6a24
3bc61658
23f3db32
4dcf37bf

Previously the runner only picked up the first level of the test suites.
Now we pick up each folder as a Mocha suite, which increases the tests
run from ~1K to 6K.

Failures in after_success don’t actually fail the build.

Turns out old Java API struggles with certain UTF-8 characters.

https://github.com/dlmanning/gulp-sass/issues/529
https://github.com/sass/node-sass/issues/1699

This is affecting JVM based build systems like Jenkins

https://issues.jenkins-ci.org/browse/JENKINS-12610
https://issues.jenkins-ci.org/browse/JENKINS-33478

Remove the cli before test

This test is super flakey for some reason, and `before` hooks also
appear to be get retried by mocha.

The was only required for when testing against LibSass < 3.3 which
is no longer the case. As such this hook serves no purpose.

Don't run tests when building a Windows release

Fixes to troubleshooting doc

package.json will not be created without npm init and a --save is required to append the installed version of package onto the package.json

Move the two CLI Usage into separate lines

Publish tests to npm

Add a nice little progress bar while downloading binary

Increase the binary fetch request timeout

I found the 1s timeout to be really fragile when testing locally.
The intent of the timeout is to prevent the install process hanging
indefinitely. It makes sense to be very generous so this increases
the timeout to 60s.

The timeout applies to both the initial connection as well as
individual packets.

Forked from #1649.

This PR adds a small ascii progress bar to the binary download.
Stalled installations make up a steady background noise of our
issues. It's my hope that by making the binary fetch more
transparent we can stem the tide of those issues.

In order to address @saper's [concerns][1] this progress bar will
respect npm's `progress` config flag.

Downloading
```
Start downloading binary at https://github.com/sass/node-sass/releases/download/v3.8.0/darwin-x64-48_binding.node
Total 2602136 [===============          ] 1566256 60% 4.9s
```
Success
```
Start downloading binary at https://github.com/sass/node-sass/releases/download/v3.8.0/darwin-x64-48_binding.node
Total 2602136 [=========================] 2602136 100% 0.0s
Binary downloaded and installed at /tmp/node-sass/vendor/darwin-x64-48/binding.node
```

[1]: https://github.com/sass/node-sass/pull/1649#issuecomment-242720257

Retry CLI specs that fail three times