Clean up arch/*/process.hh includes and std namespace issues.

Clean up arch/*/process.hh includes and std namespace issues.

arch/alpha/process.cc:
arch/mips/process.cc:
arch/sparc/process.cc:
    You really do need the headers in the .cc file.
arch/alpha/process.hh:
    Don't include unnecessary headers in another header.
    Replace with forward class declarations.
arch/mips/process.hh:
arch/sparc/process.hh:
    Don't include unnecessary headers in another header.
    Replace with forward class declarations.
    Also fix std namespace... no "using" in header files!

--HG--
extra : convert_revision : f2cd953d0f4a212bb8148cc54c329aa3c18deb89