Hello,

I've just removed modules_k/sl module. modules_s/sl was moved to modules/sl and all the other modules depending on any of sl modules were updated to use it.

The are some differences, especially looking from K sl point of view:

- statistics - S sl module had a more detailed set of stats per reply codes (they were available only via RPC). Therefore they were exported to K stats API instead of importing the K implementation. Now you get counters for common replies like 100, 400, 401, 403, 500, ... The other replies which do not mach an exact code are counted in NXX vars (e.g., 2xx, 3xx, 4xx) - there is a single API exported by the module, making available several SL send reply functions, get To-tag and register callbacks -- see modules/sl/sl.h. The callbacks framework is completely new, using new api and more compact parameters -- they were used only in siptrace and nat_traversal modules, so the impact was rather small

I did a commit per module for the updates in modules depending on former sl modules in order to be easy to trace and spot issues, therefore each developer can see very easy the changes in his/her modules.

Tests were conducted with default config and some typical cases, practically should not be a real big impact in modules -- sl reply functions from former APIs use distinct names but same parameters. The implementation was adapted to fit S SL module internals.

Testing and feedback is very much appreciate.

Cheers, Daniel