Add SoftFloat-2b package

Original files extracted from SoftFloat-2b.zip by John R. Hauser
downloaded from http://www.jhauser.us/arithmetic/SoftFloat.html
Rename softfloat/386-GCC.h as processor.h
Customize softfloat header files
Add Makefile.am for softfloat
Eliminate unused variable warnings in softfloat.c
Suppress MSVC compiler warnings in softfloat.c

warning C4146: unary minus operator applied to unsigned type, result still unsigned
warning C4244: conversion from 'type' to 'type', possible loss of data
Add MSVC makefile elements for softfloat
Specify softfloat tininess option for BFP
Remove unused softfloat definitions

The following definitions are never referenced in the
softfloat code and may clash with system definitions:
TRUE, FALSE, BIGENDIAN, LITTLEENDIAN
Define per-thread variables for softfloat

Each CPU thread will require a separate instance of
the following variables:
float_rounding_mode
float_exception_flags
Functions to get, fetch, and put softfloat operands
Add softfloat is_nan, is_neg, is_zero functions
Convert AXBR and SXBR to softfloat
Correction to is_zero functions
Correct AXBR,SXBR missing program interrupt
Add softfloat routine float_set_rounding_mode
Set rounding mode for softfloat
Convert FIEBR to softfloat
Standardize AXBR,SXBR function epilog style
Convert AEBR,AEB,DEBR,DEB,MEEBR,MEEB,MAEBR,MAEB,MSEBR,MSEB,SEBR,SEB,DIEBR
to softfloat