Automate contributors & assist changelog

Initial stabs at #255 and #254.

This modifies package.json in place before publishing. We may want to just use this as a manual command.

This outputs some information to summarize the CHANGELOG, using the messages from the commits that came after the most recent release:

```console
$ node utils/updatePackage.js
Summarize these for the CHANGELOG:
>>>>>>>>>>>>>>>
Newline at the end.

Update package.json, using name:, email: format

Summarize the CHANGELOG.

Clean up intermediary work.

Write out contributors to package.json

Put the update package in as a prepublish step.

Grab the most recent email to be used, rank devs

Initial stabbing at #254

Create CONTRIBUTING.md
Merge pull request #242 from erran/ansi-escape-modifications

Fix #238 - Convert ANSI codes even with escapeConsoleOutput unset
Fix #238 - Convert ANSI codes even with escapeConsoleOutput unset

* Update configuration defaults
* Revert the conditional escape logic to exclude the ANSI toHTML
statement (thanks for pointing this out @morinmorin)

<<<<<<<<<<<<<<<
package.json written
```

What do you think @erran? This requires nodegit.