PHP support via. Phpactor

[dantleech]

Support for PHP via phpactor.

Phpactor currently provides real completion for member access (methods, properties and constants), and can provide more options in the future (e.g. new classes, local variables, etc).

Unlike most "completion backends" it does not use a database index, and relies on the PHP package manager (composer) to locate classes - which means it will not work on the very rare projects which do not use composer.

It is also still under development so is potentially unstable. For this reason I don't recommend merging it yet - but just wanted to register the idea and see if it would be eligible for merging in the future.

[maralla]

I think it's better to implement this in a different repo. Here are the examples of implementing completers in its own repo:

• swift support
• neosnippet support