Refactor|Info: $= parses one script statement

While $: parses a line of text, $= now parses one complete script
statement, which may or may not span multiple lines.
Refactor|InfoBank: Renamed method to be more accurate

Also fixed InfoBank private implementation init.
libdeng2|Folder: More detailed error message about files not found
Fixed|ScriptedInfo: Always give a value for __file__ when running
Fixed|RuleBank|ColorBank: Values are defined in records

Presently InfoBank assumes everything is defined using blocks.
Client|Default Style: Added definitions for colors, images and rules