Replace MYSQL_inc with MYSQL_CFLAGS

Part of #1748
Replace MYSQL_lib with MYSQL_LIBS

Part of #1748
Allow overriding of LDAP_LIBS

Part of #1826
Sync schema with mydns-ng
Support mydns-ng style Y/N active field.
Restore 'aux'
docs: recursor/running: cleanup

Mark all config vars bold, all commands/parameters preformatted,
remove double escaping.
docs: recursor/running: add new(er) commands
root MX test
don't do time(0) under signature cache lock
Merge branch 'master' of github.com:PowerDNS/pdns
add signatures metric to auth, so we can plot signatures/second
test NS and CNAME pointing at the root
Merge pull request #1925 from cmouse/mydns-schema-fix

Add active to schema as expected by the code
Use qcode name instead of number
Merge pull request #1933 from cmouse/recursor-logging-type-to-name

Use qcode name instead of number
no fancy-records in tinydns generate-data.sh
output varies between versions
mydnsbackend: fix types pointing at root
lmdbbackend: fix types pointing at root