[Csnd-dev] New host API

I nearly finished refactoring ctcsound.py for the new host API. I'd like to
reintroduce the following functions in csound.h:

csoundReadScore, csoundReadScoreAsync (maybe merged with an async_mode
flag), csoundGetTable and csoundGetTableArgs.

Reading score from a string is useful when coupled with csoundCompileOrc.
csoundGetTable is interesting because it gives direct access to the memory
data of the function table.
csoundGetTableArgs can be useful when dealing with a  lot of tables.

 François