Add Exception message

[yellowbean]

Current

There is only one RuntimeError in the package

The package just throw everything as RuntimeError ,expectially if the error was originated from Hastructure , which is less human friendly to Non-Haskeller .

Propose solution

• Connection Error

• Version Error

• Engine Error

• Invalid Request Message Error for ( Deal / Assumption / Pool / Asset )

• Building type not being matched

  • The "_" clause need to be raised if match fails

[yellowbean]

requires : yellowbean/Hastructure#159

[yellowbean]

The problem is so far:

Hastructure can throw error , but Servant failed to catch such error , so HTTP response is interruptted, absbox can not get exception message from Hastructure . That's why there is a lot of "ngix" error from absbox.org