Adds internal error messages while parsing the configutarion

Before this patch, if something went wrong while loading the configuration in
memory, not in terms of syntax but other run time factors such as memory
allocation, the webserver will refuse to start and no further message was given
to the user. This patch adds "Internal Error messages" that are intend to let
the user know more information about the problem that he/she is facing.
Update status code for rule 200002

Removed the non standard compliant HTTP response status code 44 and replaced it with a 400 response status code. Refs #665
Fix segmentation fault if writing to audit log fails

A segmentation fault occurs if concurrent audit log format is enabled
(SecAuditLogType Concurrent) and writing to the log fails.
Log why writing to audit log failed

Add error description from apr_strerror() to message that is logged if
writing to audit log failed.
Don't reject a large request with ProcessPartial set
Adds regression test to SecRequestBodyLimitAction

This commits adds the following regiression test to SecRequestBodyLimitAction:
* config - SecRequestBodyLimitAction Reject (multipart/greater - chunked): passed
* config - SecRequestBodyLimitAction Reject (plain/greater): passed
* config - SecRequestBodyLimitAction ProcessPartial (multipart/greater - chunked): passed
* config - SecRequestBodyLimitAction ProcessPartial (plain/greater): passed
Fixes for Parfait errors - mostly unhandled NULL pointer dereference and data type mismatch
Code cosmetics: Place copy_rules in nice shape.

Continuation of kukackajiri's work to provide fixes for errors pointed by
Parfait. The function copy_rules had an integer as return code but it was not
filed proper neither checked by its callers. This commit just adds sanity
checks and documentation for the copy_rules function. Marking were placed
on the copy_rules callers, but the return code is not handled yet.
For kukackajiri's work, see merge request: #612
Flip allocations that happen during initialization (typically) over to use non-global apr memory pools.
Standalone: independently destroy the connection and request pools

Add independent modsecFinishConnection API that allows you to independently
destroy the connection and request pools. This is to facilitate reuse of a
connection for multiple requests.
Merge pull request #666 from derhansen/master

Uses code 400 instead of 44 in modsecurity.conf-recommended
iis: Uses code 400 instead of 44 in modsecurity.conf

Following the recent changes that has been made on:
modsecurity.conf-recommended
Merge pull request #668 from edieterich/auditlog_segfault

Fix segmentation fault on auditlog
Merge branch 'master' into iis_installer