Client enhancements to get crtime, file magic, and PE headers data

I used MSYS2 with MINGW to build libgnurx-0.dll and magic1.dll for Windows to be able to properly use python-magic.  The installer would also need to be modified to include the file magic database magic.mgc in the client installed directory.

I removed some packing detection and checksum comparison due to it having a pretty significant performance hit on larger binaries.  It may be worth it to enable those via options when a flow is run.

This also carves off the PKCS7 certs on PE files and returns them.  There might be better ways to do this.
I tried that initially and couldn't get it to work due to the threading issues with the magic lib.  Further down I have to catch the exception it throws due to that from suspending listings and attempt to reload the magic object.  

I could do an initial load with Init hook to get a successful load and then just reinit as necessary if the initial attempt was successful.  If the Init hook leaves it at None the rest of the magic checking code could be skipped.