Compile warning under linux gcc 4.8.4

[tpeterka]

In file included from /homes/tpeterka/software/diy/include/diy/collection.hpp:7:0,
                 from /homes/tpeterka/software/diy/include/diy/master.hpp:12,
                 from /homes/tpeterka/software/diy/tests/swap-reduce.cpp:10:
/homes/tpeterka/software/diy/include/diy/storage.hpp: In member function ‘virtual void diy::detail::FileBuffer::load_binary_back(char*, size_t)’:
/homes/tpeterka/software/diy/include/diy/storage.hpp:31:134: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
       virtual inline void load_binary_back(char* x, size_t count) override    { fseek(file, tail, SEEK_END); fread(x, 1, count, file); tail += count; fseek(file, head, SEEK_SET); }
                                                                                                                                      ^
/homes/tpeterka/software/diy/include/diy/storage.hpp: In member function ‘virtual void diy::FileStorage::get(int, diy::MemoryBuffer&, size_t)’:
/homes/tpeterka/software/diy/include/diy/storage.hpp:120:41: warning: ignoring return value of ‘ssize_t read(int, void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
         read(fh, &bb.buffer[0], fr.size);

[mathstuf]

See #57 for more detail.

[mrzv]

I'm going to close this in favor of #57.