ui: override default theme

This commit overide style for tree items rendering, to fit with wireframes.
It adds a new Highlight shadow, new item separator, new Selected style.
Items can also have an array of "contextual views" that will be rendered only
on mouse hovers events.
It also introduce support for Ring official colors.

Issue: #79400, #79398
Change-Id: I8d227955f9afe25240b1ece991c57a3cbf996474
diff --git a/src/views/ContextualTableCellView.h b/src/views/ContextualTableCellView.h
new file mode 100644
index 0000000..ee833ff
--- /dev/null
+++ b/src/views/ContextualTableCellView.h
@@ -0,0 +1,29 @@
+/*
+ *  Copyright (C) 2015 Savoir-faire Linux Inc.
+ *  Author: Alexandre Lision <alexandre.lision@savoirfairelinux.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.
+ */
+
+#import <Cocoa/Cocoa.h>
+
+@interface ContextualTableCellView : NSTableCellView
+
+/**
+ * List of subviews to hide/show when mouse is tracked
+ */
+@property (nonatomic) NSMutableArray* contextualsControls;
+
+@end