Merge injectify-loader and inject-loader

[vladimir-tikhonov]

Fixes #32

I've removed flow typings because I'm not familiar with flow and don't think that it will help much on such small project. Hovewer I can try to add them back if you want.
Feel free to ask any questions or request changes.

[vladimir-tikhonov]

I've added additional test in 0831925 to ensure that we don't break obj.require() calls (issue mentioned in #31). cc @rmp135

[vladimir-tikhonov]

Commit b579460 adds sourcemaps support (fixes #10)

[plasticine]

@vladimir-tikhonov This is phenomenal stuff — great work, huge effort! 👏

I’ve made a few really minor tweaks to some of the tooling and example code, but the actual library code is perfect! 👌

If you’re happy then let’s ship this and release it as 3.0.

[plasticine]

@vladimir-tikhonov apologies for the few broken commits there, looks like there were a few issues with the example/integration tests and packaging code.

[vladimir-tikhonov]

Good catches, @plasticine 👍