Fix lint when working on windows

Summary:
Fixes T4395.

Add quotes to ExecFuture strings on Windows to prevent `cmd.exe` from mucking up the command string.

Test Plan: Run `arc lint` on projects using `phpcs`. See everything working like it should.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Maniphest Tasks: T4592, T4395

Differential Revision: https://secure.phabricator.com/D9348
Allow triple backticks to be preceded by whitespace.

Summary: Fixes T5264. Allows triple backticks to be preceded by whitespace in a code block. This fixes the display of quoted code blocks, which are regular code blocks prefied with `> `.

Test Plan: Wrote and executed unit tests.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Maniphest Tasks: T5264

Differential Revision: https://secure.phabricator.com/D9388
Implementation of PhutilLexer for Python

Summary: This appears to be ~1.5-2.0x faster than pygments on my machine, which isn't as good as I was hoping for but will help. (This is ~330 ms for a 4400-line file I chose at random.)

Test Plan: Loaded a Python paste and saw highlights that approximately (or maybe exactly) match the pygments version.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9370
Fix bugs in python lexer

Summary:
Two things:

- The appearance of \\ or \' or \-followed-by-a-newline in a raw string would improperly end the string
- A disallowed newline in a string would cause an error instead of trying to continue anyway

Test Plan:
Ran it on a file that was failing for me that was something like:

    x = r'\\"'
    # hello there

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9404
Apply various linter fixes.

Summary: Applied various linter fixes.

Test Plan: Ran `arc unit` to verify things still worked.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9435
Allow `Makefile` files to contain tabs.

Summary: Add an entry to the `.editorconfig` file to allow `Makefile` files to contains tabs over spaces. Without this entry, my editor will automatically convert the tabs to spaces (which `make` does not like).

Test Plan: Opened `./support/xhpast/Makefile` and saved it. Verified that spaces weren't converted to tabs.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9436
Exclude some test data from being linted.

Summary: Currently, `arc lint --apply-patches` will patch some files which contain test data, consequently causing unit tests to file. We should either modify the tests so that they can pass linting and unit tests successfully (if possible), or just exclude them from being linted.

Test Plan: Ran `arc lint --apply-patches` and ensured that these files were not patched.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9437