Redo the FloatRegFile using unsigned integers

Redo the FloatRegFile using unsigned integers
Edit the convert_and_round function which access FloatRegFile

arch/isa_parser.py:
    recognize when we are writing a 'uint64_t' FloatReg and set the width appropriately
arch/mips/isa/decoder.isa:
    Send a 'float' to the convert function instead of a unsigned word. Do this so we dont have to worry about the
    bit manipulation ourselves. We can just concern ourselves with values.

    Use unsigned double to get movd...
arch/mips/isa/formats/fp.isa:
    float debug statement
arch/mips/isa_traits.cc:
    add different versions of convert_and_round functions
arch/mips/isa_traits.hh:
    Use an array of uint32_t unsigned integers to represent the Floating Point Regfile
configs/test/hello_mips:
    basic FP program
cpu/simple/cpu.hh:
    spacing

--HG--
extra : convert_revision : a6fca91ad6365c83025f1131d71fa1b8ee76d7bc