File Release Notes and Changelog

This release contains a number of bug fixes.  One important change
is the switch from unbuffered read/write of strings to buffer read/write of
strings.  This is following the recommendation from Jon Strabala.  We also
benefit from a number of suggestions suggested by Petr Valen.  Thanks for
these great suggestions.  Please keep them coming.

-- include a patch from Petr Velan to deal with include files related to
     util.h and pwd.h
-- make interpretation of internally generated column names of the form
   __xx in src/part.cpp
-- lock accesses to values in sharedInt32 and sharedInt64 when atomic
   operations are not available
-- rename select clause keyword distinct to countdistinct
-- address the problem with query evaluation cost reported by Petr Velan
   on 05/07/2015
-- add guards to called to strcmp to prevent nil pointer from being used
-- allocate sufficient space before calling ibis::fileManger::doRead to
   avoid recursive invocation of mutex locks (i.e., avoid a deadlock
   situation)
-- per suggestion from Jon Strabala, change all string read/write
   functions from unbuffered versions (read/write) to buffered versions
   (fread/fwrite)
-- replace std::binder1st and std::binder2nd with std::bind1st and
   std::bind2nd
-- rename ibis::util::cleanDatasets to be ibis::util::emptyCache