Make CFLAGS overridable.

If $CFLAGS is not last in the assignment, then you cannot override
flags like -O2.
verify_services: bail out with error if some service cannot be resolved

Rather than the assertion (which can even be no-oped in compile time),
which would kill cf-agent, exit the promise with a failure.
Redmine #2971: reset SIGPIPE signal handler to have a sane behavior of piped commands within child
verify_services: fix typo in message

As noticed by Chris Dituri
Add stress policy
Some stress policy I was working on.
Exotic platforms don't have IPV6_V6ONLY flag.
Merge pull request #1356 from nickanderson/stress

Add stress policy
Merge pull request #1355 from jimis/multi-tenancy

Exotic platforms don't have IPV6_V6ONLY flag.
Gets rid of the MDB_NOTFOUND messages
Fix a segmentation fault if the private key file is corrupted
Merge pull request #1357 from jeffali/fix/lmdb_locks2

Gets rid of the MDB_NOTFOUND messages
Update ChangeLog with new 3.6 features.

Structure things a bit more for improved (hopefully) readability.
Update ChangeLog regarding packagesmatching.
New function 'datatype', not documented
Our *.cf files should not be executable
Merge pull request #1359 from ediosyncratic/cf-file-perms

Our *.cf files should not be executable
Merge pull request #1358 from lpefferkorn/privkey_check

Fix a segmentation fault if the private key file is corrupted
Merge pull request #1346 from xrg/services-resolution

verify_services: bail out with error if some service cannot be resolved
Removing "Call Collect" messages
Merge pull request #1362 from cduclos/call-collect-agent

Removing "Call Collect" messages