Search instead of direct compare when checking install script

[mscdex]

Some modules are using variations on "node-gyp rebuild" in their install scripts (e.g. ws as of this writing), so it would be nice to instead do a substring search instead of an exact comparison. Making this change will prevent the need to manually set 'gypfile' to true for such packages.

[wolfeidau]

It would be nice to get this in sooner rather than later to ensure there is an accurate picture of which modules have gypfiles and which don't.

As per https://github.com/isaacs/npm/issues/1891

[isaacs]

That flag is just there to specify that we read a gypfile to fill in the scripts field implicitly. It's not intended to be used for any other purpose, or to be set by the author.

If you want to run analytics on who's using which scripts, use this view: https://isaacs.iriscouch.com/registry/_design/app/_list/scripts/scripts?scripts=install,preinstall,postinstall&match=node-gyp

[isaacs]

Here's a nicer URL: http://registry.npmjs.org/-/scripts?scripts=install,preinstall,postinstall&match=node-gyp