Test cleanup: code.yml

[Jason Garber]

I'm going to be working one YAML file at a time and posting my  
comments to the list.  No substitute for reading the diffs and yml  
files yourself, but it helps to have a summary.  I want to be very  
open about the changes.

Changes:
* Escaping needs to be different within code tags (or @ or bc.)
* Removed triple backticks as a code signature
* Switched tests that used <pre class="code> to bc.
* Removed Markdown-style indented code
* Added Textile2 double-equals block ignore
* Removed the forced observance of inline signatures within code:  
here is some *starred* code but I want some redcloth*bold*redcloth code.
* Leaving in HTML becoming <span class="caps">HTML</span>.  I don't  
see how it's useful, but Textile2 does it.  SRC doesn't yet.
* Added a test to ensure hard breaks aren't inserted between HTML  
elements (like LIs or <pre>\n<code>)

Remaining differences from Textile2:
* Textile2 doesn't seem to like multiple ==ignores== on one line
* Textile2 uses numerical entities.  I prefer SRC's already-working  
named ones.
* Textile2 doesn't observe hard breaks inside HTML elements (see:  
"and it will not put a <br /> between them")
* If something is wrapped in <notextile> tags, Textile2 still puts it  
in a paragraph

You can see how actual SRC output measures up to expected output with
   rake test:parser:code
and see how the expected output measures up to Textile 2.0.0's output  
with
   rake test:textile2:code

My AIM name is JasonGarberEMU if you want to chat.