Macros: Fixed memory leaks introduced by previous commit.

Commit 1f8c74633d41505f8f05a6bf19b7bc0839c5e1cb introduced significant
memory leaks by allocating memory for each macro value. This commit
fixes many memory leaks by reverting that commit and fixing the
function that was free unallocated memory.
Workers/Macros: Fix valgrind warning about invalid read

Not sure why it fixes it, but replacing a call in wproc_run_job
using the macro kvvec_addkv with a call to kvvec_addkv_wlen with
the exact size paramaters causes valgrind to stop issuing an invalid
read warning.
Macros: Remove more memory leaks for macros in notifications

This commit removes memory leaks for hostgroup, servicegroup,
contactgroup, and datetime macros in notifications. It also fixes
a memory leak when datetime macros are grabbed.
Config: fixed memory leak for service parents
Merge branch 'master' of ssh://git.code.sf.net/p/nagios/nagioscore

* 'master' of ssh://git.code.sf.net/p/nagios/nagioscore:
  * Fixed bug where audio alerts wouldn't work with a 0 height and width - http://support.nagios.com/forum/viewtopic.php?t=26387 (Scott Wilkerson)