Refs #37

- Changed magic constant to 1.2
- Info about total server memory consumption

Refs #37

- Added malloc overhead (sizeof(size_t) for each allocation, according to libc's malloc.c source file.
- Added minimal malloc chunk size (sizeof(size_t) * 3)
- With magic constant of 1.15, results are OK, but needs more tweaking, only tested with one set of RRs and only on a 64bit system.

Refs #37

 - Used for ahtable size estimation
 - Estimate still not precise, but getting close
 - Added malloc wrapper for trie, but allocated sizes are negligible

  Refs #37

 - Now more precise (Massif-precise at least)
 - Missing trie + ahtable estimations
 - Needs a bit of adjustment to be even more precise

 Refs #37

- Works, but there are leaks
- Missing doxygens
- The estimate is not accurate - it reports about a half of the actual consumption on a 32bit system

Refs #37

- Removed functions from zone-contents - no need for them to be public.

- Mimics BIND

Two reasons:
- There's some rare race condition in the queue implementation
- Doesn't scale and current performance is almost the same (-~2%)
- Created branch with the queue still retained for future inspection

This should be properly solved by better zone fetching API with
a) refcounting b) locking.

refs #31
fixes #30

- Added a simple list to check already inserted CNAMEs
- Removed obsolote checking functions
- Nightly test will fail, because CNAME loops will be loaded and xfr-in'd

Change-Id: Ic80408a129bf42e97b9e88392d318e89cfbad3e5

(changes in scanner intentionally skipped)