Support for tarball

[deniak]

That PR aims at allowing tarballs in echidna.
The tarball is expected to contain an Overview.html file as required by pubrules.

@tripu I'm assigning you as the reviewer but @plehegar, your feedback is welcome.

Note: .tgz and .tar.gz are not supported.

Fix #230

[plehegar]

Using mime type to detect the file type might be unreliable. How about checking that you find "ustar" at byte 257?
https://en.wikipedia.org/wiki/Tar_%28computing%29

[deniak]

The module file-type is checking the magic number to identify the type (see l.95).

[plehegar]

@deniak ok. thanks.

[tripu]

@deniak, I'd put your new test under the section fetchAndInstall(url, dest) to have it nicely grouped like the rest. And sort dependencies in package.json alphabetically.

Apart from that, OK to merge!

[deniak]

@tripu thanks for the review

[plehegar]

@deniak many thanks! let me know when this gets deployed. I'd like to test it with a publication.

[deniak]

@plehegar we just deployed v1.5.0. Feel free to publish your tar files.