Add go-wrapper support for Go 1.4 Custom Import Paths, relegating .godir support legacy and "second fiddle"

Fixes #29

I haven't run `update.sh` yet in the spirit of making this easier to review. :+1:
See the code further up, this is just moved:
```diff
-dir="$(pwd -P)"
-goBin="$(basename "$dir")" # likely "app"
```