Fix formatting of decimal values when there is no fractionSymbol.

When a currency format does not include a fractionSymbol it should be
able to format fractional values.

Fixes #2253
Split existing tests up, and add tests for Router based image URL's

Refs #2233
Fix missing HTML encoding on URL's generated by Html->meta().

The input URL was not correctly handled as an asset URL and thus was
not correctly HTML or URL escaped. This created invalid HTML when
favicon URLs included query string arguments.

Refs #2233