Changes upto v0.3.1

These changes are mostly due to patches contributed by Robert S. Thau <rst@ai.mit.edu>:

• Nested environments with the same name are now dealt with properly.
• Commands that are passed to LaTeX for processing which have environments in their arguments (e.g. a parbox command which an itemize environment as an argument) are now processed correctly. A general mechanism for users to specify the syntax of commands that should be passed to LaTeX is described in Page .
• Fixed a problem with recognizing the special command.
• Fixed bug in the generation of the index.