Implement file search

Clear found files list on clear button pressed

Make found files header bold

Enable clearing of search box with button click

Add tool tip to search box

Filter data sets on pressing Enter

Add function to filter directories

Closes #10 (closed)

sohstationviewer/view/ui/main_ui.py

@@ -406,10 +406,14 @@ class UIMainWindow(object):
             found_actions = self.search_line_edit.findChildren(
                 QAction, clear_action_name
             )
-            self.clear_search_action = found_actions[0]
+            self.clear_search_action: QAction = found_actions[0]
+            self.clear_search_action.triggered.connect(
+                self.main_window.clear_file_search
+            )
         except IndexError:
             # If the name of the clear button is changed in the C++ source of
-            # QT, nothing will be found. So, we raise
+            # QT, nothing will be found. So, we raise an error to indicate this
+            # problem.
             raise ValueError('No clear button could be found. Check its '
                              'objectName attribute using QObject.findChildren '
                              'without a name.')