use fzf instead of ctrl-p and ack.vim instead of ag.vim

[ryanong]

So much faster and better features

This ignores .gitignore correctly over ctrlp-py-matcher

[attack]

@ryanong Thanks Ryan, I will test this config for a bit before merging.

[ryanong]

The only issue with this branch is that Ag does not support searching within a path, but the responsiveness is much better.

[ryanong]

@attack fixed the bugs that were originally there. FZF is amazing you should really try it.
And replaced ag.vim with ack.vim because ag.vim is no longer supported (https://github.com/rking/ag.vim)

This also supports rg (ripgrep: a rust alternative to ag/ack) but it takes some configuring to get working as fast as ag. specifically you need to have better .rgingore file than a .agignore file as ag will automatically skip some binary files that rg won't.

[attack]

@ryanong Finally getting around to this.

I am doing this in two phases

1. allow/prefer use of rg over ag
2. replace ctrl-p

I am also testing alternatives to ack.vim (ie: ferret).

Regardless, this should result in achieving your initial goal.

[ryan-plated]

ooooo ferret looks nice going to try it!