Pages: Cannot emit empty string signals.

It leads to something that looks like a crash in Edje.
Pages: Add behaviour for weather page.
Label: Display formatted strings as well.
Widgets: Use a macro for text widgets.
Widgets: Add warm and cold color_classes.
Backing macro: Backing size larger than area.

This is to allow a 'border' around the contents by default.
Pages: Use a macro for a weather section.

They're all very similar - the bits that are different will simply not
be swallowed, and therefore not show.