Changed nexe name to include $(PlatformArchitecture).

create_nmf.py expects the binary to end with _32.nexe, _64.nexe or
_arm.nexe.
NaCl manifest is now generated successfully.
64-bit NaCl build.

Added 64-bit configuration to NaCl Visual Studio 2010 project. Define
TORQUE_CPU_STRING, TORQUE_CPU_X86_64 and TORQUE_LITTLE_ENDIAN for x86-64
CPUs.
Fix some startup issues found while running nacl build for the first time.

dSprintf implemented.
Handle Game->mainInitialise returning false.
Added scripts for zipping assets and setting up nacl gdb debug session.
Put manifest, nexe and example html site in a new directory.