abspath = function (p, /*optional*/cwd) {
    if (p[0] === '/') return p;
    cwd = cwd || process.cwd();
    return path.normalize(path.resolve(p));
}
Returns absolute version of a path. Relative paths are interpreted
relative to process.cwd() or the cwd parameter. Paths that are already
absolute are returned unaltered.

@param {String} p
@param {String} cwd
@return {String}
@api public