Compiler error in streambuf.tcc

[Kaz Nishimura]

/usr/include/c++/4.7/bits/streambuf.tcc:80:5: error: ‘std::streamsize std::basic_streambuf<_CharT, _Traits>::xsputn(const char_type*, std::streamsize) [with _CharT = char; _Traits = std::char_traits<char>; std::streamsize = long int; std::basic_streambuf<_CharT, _Traits>::char_type = char]’ is protected

[Kaz Nishimura]

Removed all the use of strstreambuf in prcserror.cc in favor of stringbuf, which also fixes issue #15 (also see issue #9).

→ <<cset 33973e23e749>>