Add 3-clause BSD license, plus dependency sub-licenses

* Include the 3-clause BSD license for Metepreter.
* Include licenses for dependencies as specified in the original Metasploit license file.
Specify Rapid7 in appropriate location in LICENSE
VS 2012 doc improvements

* Removed the old README.md from the `workspace` folder.
* Adjusted the build documentation in the main README.md.
* Added details of how to make sure VS2012 has beeen updated so that
  things are able to be build.
Support Rapid7 internal builds, fix sniffer ext

* r7_debug and r7_release configurations added.
* Make now detects if the appropriate libraries are on disk and will build
  whatever it can. If PSSDK is present in the appropriate location then it
  will attempt to build ext_server_sniffer.
* ext_server_sniffer is now buildable with VS 2012 with all the settings
  correct.
* ext_server_sniffer was failing to load once built. The cause of this was
  that the hMetSrv handle wasn't being set to a valid value prior to the
  command_register calls happening, it was being set too late. I'm not
  sure why this results in a crash, but moving this one call to a location
  prior to the command_register calls does resolve that problem.
Removal of more warnings in compilation
Remove unused project

* Accidentally added a project to the FS, this commit removes it.
Change output file names

As per @jlee-r7's request I've changed the output of both 32 and 64 bit
components so that the platform is included in the file name.

I also added "make clean" to the make script.
Remove redundant entries in makefile
Land #17, doc updates
Land #15, add a LICENSE file
Land #18, sniffer fixes
Land #19, add 'x86' to output filenames

Conflicts:
	workspace/ext_server_mimikatz/ext_server_mimikatz.vcxproj
	workspace/ext_server_sniffer/ext_server_sniffer.vcxproj