Merge 0.12->trunk

util.datamapper: Improve handling of schemas with non-obvious "type" The JSON Schema specification says that schemas are objects or booleans, and that the 'type' property is optional and can be an array. This module previously allowed bare type names as schemas and did not really handle booleans. It now handles missing 'type' properties and boolean 'true' as a schema. Objects and arrays are guessed based on the presence of 'properties' or 'items' field.

util.jsonschema: Fix validation to not assume presence of "type" field MattJ reported a curious issue where validation did not work as expected. Primarily that the "type" field was expected to be mandatory, and thus leaving it out would result in no checks being performed. This was likely caused by misreading during initial development. Spent some time testing against https://github.com/json-schema-org/JSON-Schema-Test-Suite.git and discovered a multitude of issues, far too many to bother splitting into separate commits. More than half of them fail. Many because of features not implemented, which have been marked NYI. For example, some require deep comparisons e.g. when objects or arrays are present in enums fields. Some because of quirks with how Lua differs from JavaScript, e.g. no distinct array or object types. Tests involving fractional floating point numbers. We're definitely not going to follow references to remote resources. Or deal with UTF-16 sillyness. One test asserted that 1.0 is an integer, where Lua 5.3+ will disagree.

executables: Reject Lua 5.1 early Prevents attempting to load libraries that may no longer be found and crashing with a traceback. Platforms like Debian where multiple Lua versions can be installed at the same time and 'lua' pointing to one of the installed interpreters via symlinks, there's the possibility that prosody/prosodyctl may be invoked with Lua 5.1, which will no longer have any of the rest of Prosody libraries available to be require(), and thus would immediately fail with an unfriendly traceback. Checking and aborting early with a friendlier message and reference to more information is better. Part of #1600

CHANGES: Lua 5.1 support removed (closes #1600)

util.envload: Remove Lua 5.1 method Part of #1600 Is this module even needed anymore?

util-src: Remove Lua 5.1 compat macros Part of #1600

mod_storage_sql: Remove Lua 5.1 compatibility hack Part of #1600

util: Remove various Lua 5.1 compatibility hacks Part of #1600

util.dependencies: Reject Lua 5.1, Lua 5.2 or later is now required (see #1600)