Bump Tilt to 1.4.1 to get its better encoding support

[andycox]

Tilt introduced better encoding support in version 1.4.0. In particular, this allows Stasis to correctly handle UTF-8 encoded template files (e.g., CoffeeScript) with extended Unicode characters.

For example, when a CoffeeScript file contains a string with a ↑ character (U+2191, UTF-8: E2 86 91), Stasis 0.2.0 fails with the following error:

[2013-10-24 15:01:54] Error: "\xE2" from ASCII-8BIT to UTF-8

Stasis::Options.set_template_option will pass options to Tilt for a given template type and force UTF-8 encoding in CoffeeScript templates, but Tilt 1.3.3 does not support any template encoding options. A magic comment (e.g., # coding: utf-8) does not appear to force UTF-8 encoding in a CoffeeScript file through Tilt.

However, the following was added to the Tilt::Template base class constructor in 1.4.0:

if @data.respond_to?(:force_encoding)
  @data.force_encoding(default_encoding) if default_encoding

  if !@data.valid_encoding?
    raise Encoding::InvalidByteSequenceError, "#{eval_file} is not valid #{@data.encoding}"
  end
end

This means that I can add this to a controller:

Stasis::Options.set_template_option 'coffee', { :default_encoding => 'UTF-8' }

which would then make Tilt call force_encoding('UTF-8') on all CoffeeScript templates it processes.

The only catch I found to bumping Stasis to Tilt 1.4.1 is that Tilt 1.3.4 introduced a no-op "template" for files ending in .html. This breaks some of the default copying behavior (and 4 of the tests). The simplest way to address this is to reach into Tilt and remove the template.

If I've completely overlooked a much simpler way to include Unicode characters in CoffeeScript via Stasis, please let me know. I couldn't find anything obvious and this seemed to be the most flexible solution.