Finally we get rid of the unmaintainable m_getfld()!

Finally we get rid of the unmaintainable m_getfld()!

m_getfld() was about 700 lines, 300 of them being comments -- that's 42%!
m_getfld2() is 240 lines, 30 of them being comments. That's only half as
much code. Most important, however, is that this code is understandable
and thus maintainable. We escaped the dead end of the heavily optimized
m_getfld() be re-writing it from scratch. (Thanks to Philipp Tacaks!)

m_getfld2() is line-based and not character-based like m_getfld(). This
change spared us to keep digging into stdio internals or implementing
our own I/O buffering. We are now portable to any standard-conforming
stdio implementation.