Add option to treat docblocks as pre-formatted reST

[c2nes]

javasphinx-apidoc attempts to mimic the Javadoc tool by converting docblocks from HTML + Javadoc tags into reST. Any pre-formatted reST placed into docblocks will be mangled by this process. An option to javasphinx-apidoc to treat all docblocks as pre-formatted would provide an option for people who would prefer to mark up their docblocks in reST.

[kristiansebastian]

I also think an option to javasphinx-apidoc should be enough.