migrate to php-parser v3.x

[taoso]

migrate again

[taoso]

Hello guys @EvanDotPro @gianarb @sensorario @shawncplus @weynhamz

The php 7.2 has been released. And the php-parser v1.x is too old to support the new php version.

We need to migrate the php-parser to the latest version. And it is time to only support PHP 5.6+ and PHP 7.x.

[taoso]

By the way, I am a PHP developer and a heavy Vim/NeoVim user. I am maintaining the phpcd.vim and phpfold.vim, both of which make Vim/NeoVim better for PHP developing.

And I would like to apply to join your php-vim group, and make Vim/NeoVim better for PHP developer.

[taoso]

Is there any body?

[mgallego]

Please review and accept the PR if is possible

[gianarb]

Thanks guys and sorry for the huge delay

[taoso]

@gianarb would you like to make me join your group?