I've tried loading up 2.3.1-dev with the 2.2.6 Bookshelf against Forge 22, 24, and 29 and no such luck:

crash-2016-02-02_11.58.12-client.txt

The -dev build is only for using in a dev environment. Just use the normal jar.

http://minecraft.curseforge.com/projects/neotech/files/2279569/download