Amd64 installer generation

Copy-pasted and customized bdist-wininst.py from python libs into sympy.
Added new command bdist_wininst_amd64 to setup.py
Added tools/windist-9.0-amd64.exe because some linux distro do not install it as part of python.
Fixed generated exe name: instead of sympy-0.7.2-git.linux-x86_64.exe, sympy-0.7.2-.win-x86_64.exe

To build win-amd64 installer the following command needs to be issued:
"python setup.py build bdist_wininst_amd64"
which will generate "dist/sympy-0.7.2-.win-x86_64.exe"