When the number of files in a project directory is above the max
limit switch back to a mechanism to read directory content only
when the corresponding folder is expanded in the treeview.
When the command core:find-file is invoked the command core:open-file
is executed instead because the complete list of the project's
files is not available.
When a project search is done we search through all the files within
the project dir without indexing them.
Address issues #217#203#183.