stub for monadic IO in CCPrint
fix bug in test
CCError: retry and choose combinators
doc
CCList.sort_uniq
CCArray.lookup for divide-and-conquer search
fix bug in CCPrint.to_file
add BTree partial implementation (not working yet)
CCFQueue: logarithmic access by index
bugfixes in BTree (insertion should work now)
constructors for 1 or 2 elements fqueues
simple interface to PrintBox now more powerful
monadic operator in CCList: map_m_par
doc
doc
registered printers for CCError.guard,wrap1,etc.
CCHashtbl: open-addressing table (Robin-Hood hashing)
conversions for CCString
small change in makefile
merge from master