Implement an html documentation generator similar to Haddock

[janmasrovira]

Current goals:

• It will be part of the compiler, not an external tool (at least for now).
• It should be possible to write Haddock comments, or Judoc comments (as we shall call them for now), to document different parts of a program. On the first iteration we will only support functions. Later we want to add
  1. Inductive types
  2. Constructors
  3. Modules
  4. Individual function arguments (to be discussed)
• Will support a very basic language described below. In the nearish future we may want to discuss if we want to support a popular markup language, such as Markdown, and rely on an existing parser.
• The Judoc comments need to be scoped and type checked.

The initial syntax of Judoc comments is very simple and will change in the future.
A Judoc comment spans multiple lines. Each line must start with --- (note the trailing space).
A Judoc comment can have text and inlined expressions (surrounded by ;). Having ; as a delimiter is convenient because it is already a reserved symbol of the language (needed for parsing).

Example:

module Example;

--- The identity function.
--- Example:
--- ;id Type; is the same as ;Type;
id : {A : Type} -> A -> A;
id a := a;

end;

Related:

• Print out the comments in the HTML output #1359