Added fix for displaying buttons on Ubuntu

ui/callButton/callButton.css

@@ -66,3 +66,7 @@ QPushButton#grey
     height: 40px;
 }
 
+QPushButton:focus {
+    outline: none;
+}
+

ui/emoteButton/emoteButton.css

@@ -15,4 +15,8 @@ QPushButton:hover
 QPushButton:pressed
 {
    background-image: url("ui/emoteButton/emoteButtonPressed.png");
-}
+}
+
+QPushButton:focus {
+    outline: none;
+}

ui/fileButton/fileButton.css

@@ -15,4 +15,8 @@ QPushButton:hover
 QPushButton:pressed
 {
    background-image: url("ui/fileButton/fileButtonPressed.png");
-}
+}
+
+QPushButton:focus {
+    outline: none;
+}

ui/sendButton/sendButton.css

@@ -15,4 +15,8 @@ QPushButton:hover
 QPushButton:pressed
 {
    background-image: url("ui/sendButton/sendButtonPressed.png");
-}
+}
+
+QPushButton:focus {
+    outline: none;
+}

ui/videoButton/videoButton.css

@@ -66,3 +66,6 @@ QPushButton#grey
     height: 40px;
 }
 
+QPushButton:focus {
+    outline: none;
+}