Merge pull request #302 in SNORT/snort3 from ~JOCORNET/snort3:memory to master

Merge pull request #302 in SNORT/snort3 from ~JOCORNET/snort3:memory to master

Squashed commit of the following:

commit 96b932a314ef5a906bcf6aa144853c36d1a4410f
Author: Joel Cornett <joel.cornett@gmail.com>
Date:   Mon Feb 29 15:21:08 2016 -0500

    prevent allocation reentry

commit 69026ddc973bc19e4ca0f22609f8de2bf0f872f3
Author: Joel Cornett <joel.cornett@gmail.com>
Date:   Mon Feb 29 10:38:15 2016 -0500

    added checks

commit f3a80f12654a4451ab5a061f3249745deb3b13c0
Author: Joel Cornett <joel.cornett@gmail.com>
Date:   Mon Feb 29 10:15:44 2016 -0500

    fixed memory tracking in main thread, added debug message for memcap calc

commit 95d233fc038cbb0a96832fb3137de13822141669
Author: Joel Cornett <joel.cornett@gmail.com>
Date:   Fri Feb 26 15:14:20 2016 -0500

    Added per-thread memcap calculation