Add paths-searched event to the scan-handler

This allows the interface to know how many total paths were searched

src/project.coffee

@@ -302,6 +302,10 @@ class Project
     task.on 'scan:result-found', (result) =>
       iterator(result)
 
+    if _.isFunction(options.onPathsSearched)
+      task.on 'scan:paths-searched', (numberOfPathsSearched) ->
+        options.onPathsSearched(numberOfPathsSearched)
+
     deferred
 
   # Private:

src/scan-handler.coffee

@@ -3,13 +3,23 @@
 module.exports = (rootPath, regexSource, options) ->
   callback = @async()
 
+  PATHS_COUNTER_SEARCHED_CHUNK = 50
+  pathsSearched = 0
+
   searcher = new PathSearcher()
   scanner = new PathScanner(rootPath, options)
 
   searcher.on 'results-found', (result) ->
     emit('scan:result-found', result)
 
+  scanner.on 'path-found', ->
+    pathsSearched++
+    if pathsSearched % PATHS_COUNTER_SEARCHED_CHUNK == 0
+      emit('scan:paths-searched', pathsSearched)
+
   flags = "g"
   flags += "i" if options.ignoreCase
   regex = new RegExp(regexSource, flags)
-  search regex, scanner, searcher, callback
+  search regex, scanner, searcher, ->
+    emit('scan:paths-searched', pathsSearched)
+    callback()