Adding exploit for CVE 2012-4915

Initial commit.

Major functionality working. A bit of polish is still needed in a few
spots to handle exceptions and such.
Improvement for CVE 2012-4915

Made two tiny improvements based on Meatballs' points

- Added handling for 127.0.0.1 as DB_HOST
- Added a note in the description about it changing the pasword
Adding a check function

Because it makes sense. The non-vulnerable versions doesn't have
/libs/pdf.php.

So pretty simple.
Changes based on Sinn3r's feedback

A bucket-load of changes!

- Added a fallback for if there is no Set-Cookie header
- Added a check if the cookie we produce is simply empty, meaning we
failed something :(
- Removed use of flatten. Though I may look into making that extraction
better
- Changed cgi requests to use vars_(post|get)
- Clarified a few status prints
- A few EOL space fixes
Adding DB error handling

As per sinn3r's suggestion, adding handling for the most common MySQL
errors.

Also adding HostNotPrivileged, which I encountered during my testing.
Merge branch 'master' of github.com:CharlieEriksen/metasploit-framework into CharlieEriksen-master
Improve the module