Stix ipwatch v1.11

Adds support for STIX-based indicators for feature #1095.

From previous PR: #1096:
Ensured each commit compiles.
Modified WatchListData data structure in util-ipwatchlist.h to use a char* instead of a Signature.
Resolved comments from #1096 

From previous PR: #1060:
Organized and updated unit test function names to start with upper case letter in detect-watchlist.c and detect-smtp-indicators.c.
Modified InitWatchDataFully to properly invoke free.
Updated to meet QA standards.

<pre>
In file included from suricata-common.h:316:0,
                 from util-ipwatchlist.h:22,
                 from util-ipwatchlist.c:18:
util-ipwatchlist.c: In function ‘AddIpaddressesToWatchList’:
threads.h:121:48: warning: ‘mutex’ may be used uninitialized in this function [-Wmaybe-uninitialized]
 #define SCMutexUnlock(mut) pthread_mutex_unlock(mut)
                                                ^
util-ipwatchlist.c:132:14: note: ‘mutex’ was declared here
     SCMutex *mutex;
              ^
</pre>