Firebird V1.5.1 released

Changes from previous version: This release adds a charset improvement, allowing use of NONE as a fully transparent charset everywhere. (Changes were made in the engine to make the character set NONE more friendly about reading / writing data from and to fields of another character set.) It adds the config-driven ability to abort a server process in the case of bug checks or structured exceptions (to produce a core dump). Firebird Superserver has a link-time backward compatibility issue with the NPTL (Native POSIX Thread Library) that may cause it to be unstable on Linux distribu tions that enable the NPTL in the GNU C.The new NPTL builds of Superserver should solve these problems.