And remove my own opinions...

This is a PR to remove the opinionated lines from the Node.js .gitignore file.

I do not believe that Github's pre-baked .gitignore files should be promulgating opinions, especially in a community that is as fresh as the Node.js community.  Questions of what should be checked in should be a decision made on an organization-by-organization basis, or left up to the individual.  Github's inclusion of opinion in these files puts unnecessary authority behind that opinion, which can have the negative side-effect of people following without thinking.

These aren't really common patterns in the Node world, and if a Node project includes one of these types as files, they're as likely to want to include them in the project as not (`*.csv` is as likely to be a data source as `*.json`).

This re-covers the http://nodejs.org/api/addons.html case for which the "build" directory was added in 00686415, but doesn't break cross-environment projects that use the build directory for including concatenated/minified source. Mazel tov!

Now linking to the official npm FAQ entry (with tl;dr) rather than straight to mikeal's blog post

The "build" directory is lost in this refactor, as many JS projects
do wish to include a minified/concatenated version of their source
in the "build" folder in source control.

This is to exclude compiled code from nodejs addons.
Reference: http://nodejs.org/api/addons.html

according to the community since recent changes.

see: http://www.mikealrogers.com/posts/nodemodules-in-git.html
by @mikeal
(cherry picked from commit 44b47ec5bd0222ccf55efe5bcdb8bd3c55271803)