app_python	Avoid collission in name space - rename init_modules to ap_init_modules
nathelper: improved add_contact_alias() description
- thanks to Dan Christian Bogos for pointing out the deficiency
(cherry picked from commit c04f9554df58b1323a46f6e40337fa34b34f1cc9)
dbtext database definition: several fields in subscriber can be null
fixes for centos rpm specs

- updates for rtpengine and the new modules

(cherry picked from commit 16fd690d1857dfb16681d918f11ed0863cd3845c)
kamctl: supress all output of which command searching for g/readlink

- based on patch and report by Morten Tryfoss, FS#492

(cherry picked from commit ed301d16f30195d9352245f782269f2b3ddf40cf)
Merge branch '4.2' into lazedo/4.2.1