Crit! path.relative trim first symbol of dirname

**Description:**
Calling `path.relative('.', 'root/app') ` return 'oot/app' instead of 'root/app'

**Expected:**
'root/app'

**Problem at:**
https://github.com/browserify/path-browserify/blob/master/index.js#L23

**Fiddle (isolated function):**
https://jsbin.com/cinaxatugo/1/edit?js,console