Adding .hgignore (copied from default branch).

.hgignore

+.gdb_history
+.purify
+.svn/
+Makefile$
+Makefile.pre$
+TAGS$
+autom4te.cache$
+build/
+buildno$
+config.cache
+config.log
+config.status
+config.status.lineno
+db_home
+platform$
+pyconfig.h$
+python$
+python.exe$
+reflog.txt$
+tags$
+Lib/plat-mac/errors.rsrc.df.rsrc
+Doc/tools/sphinx/
+Doc/tools/docutils/
+Doc/tools/jinja/
+Doc/tools/jinja2/
+Doc/tools/pygments/
+Misc/python.pc
+Modules/Setup$
+Modules/Setup.config
+Modules/Setup.local
+Modules/config.c
+Modules/ld_so_aix$
+Parser/pgen$
+Parser/pgen.stamp$
+^core
+^python-gdb.py
+^python.exe-gdb.py
+^pybuilddir.txt
+
+syntax: glob
+libpython*.a
+*.swp
+*.o
+*.pyc
+*.pyo
+*.pyd
+*.cover
+*.orig
+*.rej
+*~
+Lib/lib2to3/*.pickle
+Lib/test/data/*
+Misc/*.wpu
+PC/python_nt*.h
+PC/pythonnt_rc*.h
+PC/*.obj
+PCbuild/*.exe
+PCbuild/*.dll
+PCbuild/*.pdb
+PCbuild/*.lib
+PCbuild/*.exp
+PCbuild/*.o
+PCbuild/*.ncb
+PCbuild/*.bsc
+PCbuild/Win32-temp-*
+__pycache__