mainwindow: Add '...' to fetch, push, pull, and stash buttons

These launch a separate dialog so use '...' to provide a visual indication.

Closes #51

Signed-off-by: David Aguilar <davvid@gmail.com>

cola/views/mainwindow.py

@@ -33,10 +33,10 @@ def __init__(self, parent=None):
         self.rescan_button = qt.create_button('Rescan', layout)
         self.stage_button = qt.create_button('Stage', layout)
         self.unstage_button = qt.create_button('Unstage', layout)
-        self.fetch_button = qt.create_button('Fetch', layout)
-        self.push_button = qt.create_button('Push', layout)
-        self.pull_button = qt.create_button('Pull', layout)
-        self.stash_button = qt.create_button('Stash', layout)
+        self.fetch_button = qt.create_button('Fetch...', layout)
+        self.push_button = qt.create_button('Push..', layout)
+        self.pull_button = qt.create_button('Pull...', layout)
+        self.stash_button = qt.create_button('Stash...', layout)
         self.alt_button = qt.create_button('Exit Diff Mode', layout)
         self.alt_button.hide()