Use parse method from transform context

[unstubbable]

This depends on rollup/rollup#1945. It removes acorn as a dependency (though it's still a dev dependency for the tests) and uses the parse method that is exposed via the transform context instead.

fixes #275 (by providing the acornInjectPlugins option to rollup)
(maybe others?)
closes #237

TODO:

• change rollup version to 0.56.0 when it has been published

[unstubbable]

I updated rollup to 0.56 and the tests are passing now. @lukastaegert This is now ready for a review.

[lukastaegert]

Looks good, thanks!

[deavial]

is there some sort of config change needed for this. I am using rollup 0.56.4 and am working correctly on rollup-plugin-commonjs 8.3.0. Any version above that (8.4.0, 8.4.1, 9.0.0) breaks the build with parse is not a function

[rockerest]

I am having the exact same issue as @victoriafrench.

Any version later than 8.3.0 of this plugin throws parse is not a function.

Edit:
Apologies, I was using grunt-rollup. After installing rollup manually, rollup-plugin-commonjs' peer dependency of rollup>=0.56 was satisfied, which gave me the false sense that it would use that version. I removed my reliance on grunt-rollup and this plugin is now working fine at version 9.0.0.

[lukastaegert]

@victoriafrench 8.4.1 should actually be working as it is identical to 8.3.0 (if I released it correctly). Otherwise I would assume that you are sharing @rockerest's issue i.e. you are unknowingly consuming rollup via a secondary dependency that pulls in an older version. In this case, please open an issue for that dependency.

If you can confirm that 8.4.1 really does not work, please let me know so that I can attempt another fix.