Add support for --exclude.

[brobeson]

• Add a configuration setting for the exclude patterns. Check if lizard supports multiple --exclude flags per command. If it does, the setting should be an array of strings. Otherwise, a single string.
• Add --exclude flags to the Lizard command.
• Document the new setting in the readme file.

[brobeson]

Lizard does not honor the --exclude option when scanning a specific file. I need to figure out a way to have the extension match the excludes with the active document to see if it should be scanned. The match algorithm needs to honor glob expressions: * and ?.