Detect and run tslint for TypeScript projects

[smhxx]

Hi, all! This is just a simple addition to the build-package scripts which adds tslint to the list of linters that the script will detect and run if present. It requires a couple extra LOC vs. eslint/coffeelint because of the type-checking, which requires a configuration file to be passed to the linter, but other than that, it's essentially identical. Let me know if any changes are required. Thanks! 😄

Just as a heads-up before merging, there may be value in letting this sit until Atom 1.22 hits the stable channel; I'll leave that to the maintainers to decide. Since many type definitions (including Atom's) are published to the @types scope on npm as part of the DefinitelyTyped project, it's not at all unlikely for users to run into atom/apm#702 and get caught in an infinite loop of apm failing to install the package. This issue was fixed by atom/apm#705, and is included in the current beta release of Atom 1.22.

As an example of what I'm talking about, here is the log of a mock Atom package being installed (unsuccessfully) by Atom 1.21, and here is the log of the same build running as-expected against Atom 1.22. If the potential wonkiness caused by that bug in the previous version of apm is a concern, merging can certainly wait until 1.22 becomes the latest stable release. 👍

[smhxx]

Ah, good point. It would hang on the installation, not the linting step, so these changes wouldn't introduce any issues that wouldn't be happening already.

[smhxx]

Good feedback, I'll try to cut out a slice of time tonight to make these changes. 👍