test/unit: removed search on modules_k folder
test/unit: kill using application name

- on some OS, killall with full path doesn't work
- kamailio is searched first, being default flavour now
test/unit: Makefile option to run individual test unit

- head parameter swapped to work on bsd/darwin
test/unit: 1.sh updated to work with latest kamailio
test/unit: README updated with more details about running unit tests
core: exit with -1 if there is a mismatch in version of module and core

- return code to shell 0 is like succesful run, some scripts not being
  able to say it was a failure to start
sms: declare inline functions static to work with clang linker

- otherwise it results in no symbol found at module loading time
benchmark: declare inline functions static to work with clang linker

- otherwise it results in no symbol found at module loading time
test/unit: 2.sh updated to work with latest kamailio
core: memlog and memdbg default value is L_DBG+1

- too verbose if just trying to use debug=3 in kamailio.cfg and mem
  operations are useful only on troubleshooting memory, which is not the
  typical troubleshooting case