Replace gzstream by boost::iostreams::gzip_(de)compressor: by Bo Peng (ben.bob@gmail...

Replace gzstream by boost::iostreams::gzip_(de)compressor: by Bo Peng (ben.bob@gmail.com)
	* src/buffer.C, use filtering_ostream
	* src/lyxlex_pimpl.h, .C, use filtering_istreambuf
	* src/Makefile.am,  src/support/Makefile.am, src/tex2lyx/Makefile.am, use BOOST_IOSTREAMS
	* remove src/support/gzstream.h, .C
	* add needed boost files boost/boost/iostreams/device/file_descriptor.hpp,
     device/mapped_file.hpp, detail/system_failure.hpp,
		 detail/config/windows_posix.hpp

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@13706 a592a061-630c-0410-9148-cb99ea01b6c8