A C++ port of the URL parsing and sanitization provided by url-py

1. Performance -- to be faster than url-py for existing Python projects.
2. Standardization -- of how we interpret and sanitize URLs across projects.
3. Relaxed parsing -- to accept and work with the "URLs" we see in crawling, even when malformed.

Rather than accept only RFC-compliant URLs, this library's parsing of URLs is based almost exclusively on Python's own urllib. It is relatively permissive, but we've used it quite extensively through url-py and have come to understand its interpretations.

To launch the vagrant image, we only need to vagrant up (though you may have to provide a --provider flag):

vagrant up

With a running vagrant instance, you can log in and run tests:

vagrant ssh
cd /vagrant

make test

Tests are run with the top-level Makefile:

make test

These are not all hard-and-fast rules, but in general PRs have the following expectations:

• pass Travis -- or more generally, whatever CI is used for the particular project
• be a complete unit -- whether a bug fix or feature, it should appear as a complete unit before consideration.
• maintain code coverage -- some projects may include code coverage requirements as part of the build as well
• maintain the established style -- this means the existing style of established projects, the established conventions of the team for a given language on new projects, and the guidelines of the community of the relevant languages and frameworks.
• include failing tests -- in the case of bugs, failing tests demonstrating the bug should be included as one commit, followed by a commit making the test succeed. This allows us to jump to a world with a bug included, and prove that our test in fact exercises the bug.
• be reviewed by one or more developers -- not all feedback has to be accepted, but it should all be considered.
• avoid 'addressed PR feedback' commits -- in general, PR feedback should be rebased back into the appropriate commits that introduced the change. In cases, where this is burdensome, PR feedback commits may be used but should still describe the changed contained therein.

PR reviews consider the design, organization, and functionality of the submitted code.

Certain types of changes should be made in their own commits to improve readability. When too many different types of changes happen simultaneous to a single commit, the purpose of each change is muddled. By giving each commit a single logical purpose, it is implicitly clear why changes in that commit took place.

• updating / upgrading dependencies -- this is especially true for invocations like bundle update or berks update.
• introducing a new dependency -- often preceeded by a commit updating existing dependencies, this should only include the changes for the new dependency.
• refactoring -- these commits should preserve all the existing functionality and merely update how it's done.
• utility components to be used by a new feature -- if introducing an auxiliary class in support of a subsequent commit, add this new class (and its tests) in its own commit.
• config changes -- when adjusting configuration in isolation
• formatting / whitespace commits -- when adjusting code only for stylistic purposes.

Small new features (where small refers to the size and complexity of the change, not the impact) are often introduced in a single commit. Larger features or components might be built up piecewise, with each commit containing a single part of it (and its corresponding tests).

In general, bug fixes should come in two-commit pairs: a commit adding a failing test demonstrating the bug, and a commit making that failing test pass.

Whenever the version included in setup.py is changed (and it should be changed when appropriate using http://semver.org/), a corresponding tag should be created with the same version number (formatted v<version>).

git tag -a v0.1.0 -m 'Version 0.1.0

This release contains an initial working version of the `crawl` and `parse`
utilities.'

git push origin