Refactor eval code (gokcehan#1591)

* 1

* globsearch

* hidden

* some more options

* ignorecase and ignoredia

* fix ignorecase/ignoredia

turns out position and loadfile are required here too since the list of
files can change (similar to hidden option)

* incfilter/incsearch

* mouse

* some more options

* preview

* remaining bool options

* fix more options that can change list of files

* Add applyLocalBoolOpt

* Use applyLocalBoolOpt

* Add position and loadfile fixes