webserver: print PDNSExceptions

previously they'd get handled as (...)
s/AhuException/PDNSException/ in docs
jsonstat: accept ints as strings or ints
json webserver: check for presence of command
json webserver: return masters as an Array
json webserver: add new 'zone' command

Replaces get-zone. Intended to replace zone-rest in the future, also
create/delete of zones should also go through this.
recursor json: put command into command var

Just like in the Auth.
auth webserver: fix invalid JSONP on errors
json get-zone: properly return error if zone doesn't exist
Enable subdir-objects for automake-1.14

Fixes warnings about source files in subdirectories, without having
this option enabled.
recursor json: implement zone command
recursor json: reimplement domains list using rapidjson

Note that this changes types of servers and rdbit.
json: Remove old get-zone implementations

pdnscontrol users must upgrade to at least 4c0e059731.
Specify how to use pipe abi-versions 1, 2, and 3 with DNSSEC.
Add support for include-dir to recursor command line
Merge pull request #993 from davidstrauss/master

Document pipe auth and scope fields for all abi-versions
Merge pull request #991 from zeha/automake-1.14

Enable subdir-objects for automake-1.14
Merge pull request #995 from cmouse/include-dir-recursor

Add support for include-dir to recursor command line
Merge pull request #992 from zeha/ws

Land json webserver changes
Add 'extended' database schema. Add domain metadata and TSIG support to original database schema.