Update roles to version 1.0.6

Roles 1.0.5 does not work properly with meteor 0.6.5 and up.
See https://github.com/alanning/meteor-roles/commit/3d2b282de96273b4fdb34cfe54ce2def46f8d735
Merge pull request #4 from Joris-van-der-Wel/master

Update roles to version 1.0.6