Add VirusTotal Scanner Utility

[SeeRM #8733] This a tool that uses VirusTotal's public API to submit
a malware sample for analysis. As an offensive tool developer, this
would provide a convenient way to check and see how AVs react to
something we write.
Adds a timeout to wait_report method

In case it takes too long to get a report, the method will give up
checking after one hour. The user can still manually check the report
from the analysis link given earlier.
Update documentation
Use $stdout
Add rspec
Update rpsec and the script
Add a post module that checks with VirusTotal with a checksum

This post module will submit a SHA1 checksum to VirusTotal to see
if it's a malicious file.
Update the post module
Correct a typo

They caught me. Thanks HD.
Have a default API key

Modules now should have a default API key. See the following for
details:
http://blog.virustotal.com/2012/12/public-api-request-rate-limits-and-tool.html
Update the use of report_note
Update description

key is no longer required.
Change default key to Metasploit
Change the post module's default api key as well (to Metasploit's)
use session_host instead
Land #2851, @wchen-r7's virustotal integration