Create find model outside of the find view
Create both views in one shot

Now cmd-g works when the find-in-project view is up, so the find-view 
must be up as well
History is now shared between the in buffer and in project view

Fixes #148
Pull the current-marker-from-selection decision into the model
Specs
Find selections always open when either find view is open
Update the buffer model on search in project
:lipstick: Rename poorly named things
Merge pull request #282 from atom/bo-shared-history

Share history between find in buffer and find in project