core: refactored DNS primitives and removed DNSSEC support from core

The library functions can now be easily overwritten by modules(dnssec) to allow enhanced resolving capabilities
modules/dnssec New dnssec resolver module based on libval

To use, simply load the module
It will overide the system resolvers (i.e. gethostbyname, res_search) with libval's provided wrappers that support
DNSSEC.
Further functionality will be added.
modules/dnssec Added copyright notices

Also forgot a memset..
modules/registrar: Remove unnecessary BRANCH_FAILURE flags

Functions that run in an event route require the EVENT_ROUTE / REQUEST_ROUTE
flag set, not the BRANCH_FAILURE_ROUTE flag
core: Allow colon separated tokens in event_route names

- Event routes can have named routes following the format:
-- <module>:<event>:<name>
-
modules/tm: Enable named branch_failure routes

- branch failure routes must be named with the format:
-- "tm:branch-failure:myroute"
- and enabled with the function:
-- t_on_branch_failure("myroute")
modules/tm: documentation: Updated branch_failure route name format

- Updated event_route[tm:branch-failure:name] documentation
- Updated t_next_contact_flow function
modules/pipelimit: check correctly for all arguments in mi_set_pipe
srdb1: add new db-private generic pointer to struct db1_res
db_mysql: fix segfault when recursive queries are made

The MySQL result object (MYSQL_RES) should not be stored within the
srdb1 connection object, but rather within the srdb1 result object.
Otherwise recursive queries overwrite each other's result sets, which
results in segfault.
pkg/kamailio/(centos|fedora): Updated .spec

- Added sipt module
- Increased rel to dev2
modules/registrar: unescape path header received param value
modules/path: b/f generate valid received param value
modules/registrar: fixed bug in un-escaping of path/received
modules/registrar: unescape received value using kcore function

- Now that unescaped received value goes into separate buffer, it is
  possible to use kcore unescape function.
modules/path: unescaped received param value also in path rr callback
core: safety check for content-lenght size in tcp read

- avoid getting negative
- upon a report by Kevin Wojtysiak
Merge branch 'dnssec'

Added support for DNSSEC as module
xcap_server: init etag variable for PUT operations

- the function xcaps_get_db_etag() may not found a record to db and will
  not initialize it, resulting in bogus value passed to
  check_preconditions()
- reported by Juha Heinanen, FS#283
siputils:  added new function is_supported(option)

- Checks if given option is listed in any of the Supported: headers of
  the request.