Added documentation for new core function disassemble

Signed-off-by: Vasudev Kamath <kamathvasudev@gmail.com>
Added .. versionadded: 0.9.13 and quoted the arguments. Also added
missing true for python code generation example.

Signed-off-by: Vasudev Kamath <kamathvasudev@gmail.com>
Merge pull request #417 from copyninja/disassemble-docs

Added documentation for new core function disassemble
Add versionadded directives for macroexpand and macroexpand-1.