Solium Integration, Linting Refactor

[shrugs]

• 📘 I've reviewed the OpenZeppelin Contributor Guidelines
• ✅ I've added tests where applicable to test my new functionality.
• 📖 I've made sure that my contracts are well-documented.
• 🎨 I've run the JavaScript linter (npm run lint:fix) and fixed all issues.

Fixes #656
Closes #556

🚀 Description

I cherry picked @azavalla's first commit to make sure that contribution is counted. Added npm script and travis integration as well as a secondary refactor commits.

I marked things like arg-overflow, security/no-inline-assembly, security/no-low-level-calls, and security/no-block-members as warnings. Note that warnings don't fail the travis script

For each rule still producing a warning:

1. We can disable it altogether because OZ has reason to use this feature
2. We can leave it as a warning to inform users (but some might be unnecessarily alarmed at the warnings generated)
3. We can modify the code to fix it, which might change api surface / logic

Some issues we can't fix for backwards-compatibility reasons (namely, uppercase for public variables in ERC20), so I've added the ignore directives (but those are, ironically, being ignored, probably because it's a beta feature).

[shrugs]

I fixed each set of lint errors iteratively in separate commits; to do a review, please check each commit separately (so you can make sure that that commit exclusively contains whitespace changes, for example).

[shrugs]

A key note is that 0 logic has been changed (if it has, let me know!!) so this should have 0 external effect to things that depend on zeppelin-solidity.

[frangio]

Checked line by line, only aesthetic changes.