Base support

[wooorm]

Stuff like gulp also supports a base (often similar to cwd) of files.
In gulp, files are read from globs (say foo/bar/**/*.js). The base is the stuff before the glob starts (so foo/bar/). And in gulp, when writing files to another folder (baz), the base is stripped and the given folder is used before the matched file (such as baz/qux.js and baz/qux/quux.js).

I feel that currently .cwd is used where actually a .base would be more apt.