let functional actions be the last callbacks to be called with selected items

[ViRu-ThE-ViRuS]

okay I am noticing that if we use a action which is a lua function, lspfuzzy will automatically set the qflist and open qflist, which might defeat the purpose fo the action argument. We can let action take complete control over what happens with the selections, which makes it more like the last callback.

I suggest letting the call return after calling functional action.

builds on #27

[ojroques]

Done, let me know if it doesn't work as expected.

[ViRu-ThE-ViRuS]

perfect! Thanks!