[Bind] Do not skip parameters in documentation

Multiple parameters may share a single description. The DocProcessor
will now correctly generate DocumentationParameters for each of them.
[Bind] Add NoIndent option to BindStreamWriter
[Bind] More aggressive trimming of documentation strings
[Bind] Propagate ComputeSize attribute in cloned Parameters
[Bind] Make documentation output closer to previous xslt implementation
[Bind] Move documentation generation to DocProcessor class

This de-duplicates a large amount of code that is shared between the
various ISpecWriter implementations.