Added option 'env' to the SCons build scripts to support overriding the ENV part of the build environment.  This is mostly to support Windows builds in cases where SCons cannot find the correct paths to the Windows SDK, as these paths cannot be passed through shell environment variables.

Enabled "Buffer Security Check" on for the Windows SCons build and added the linker option /OPT:ICF as an optimization.

Added the V8 benchmark suite to the repository.


git-svn-id: http://v8.googlecode.com/svn/trunk@101 ce2b1a6d-e550-0410-aec6-3dcde31c8c00