Add desktop_linux_privilege_escalation module
Small bugfix (incorrect filename in data directory)
Removed redundant string "linux_" from exploit name
Converted LD_PRELOAD library from precompiled binary to metasm code.
Removed binary files from pull request (the code has already been converted to metasm)
Fix #4246 - Access payload_exe information correctly

This fixes an undef method 'payload_exe' error. We broke this when
all modules started using Msf::Exploit::CmdStager as the only source
to get a command stager payload. The problem with that is "payload_exe"
is an accessor in CmdStagerTFTP, not in CmdStager, so when the module
wants to access that, we trigger the undef method error.

To be exact, this is the actual commit that broke it:
7ced5927d8807e385c0375a25ef71aef404d3036

Fix #4246
Use DNS names
Add Android cookie theft attack.
Use the hash to pass the script.
Add patch discovery date.
Add ProjectSend Arbitrary File Upload module
Move it to a common method
one line if statement
Add hint for exploit on old devices.
Land #4357, @Meatballs1 Kerberos Support for current_user_psexec
Added underscore to user regex in smart_hashdump.rb to support usernames that contain underscores. Issue #4349.
Land #4463, smart_hashdump user regex update
override default attr for OptRegexp

Rather than literally returning the default Regex object, override the accessor
to return the string representation. This allows the RPC backend to properly
serialize the options hash values, since msgpack does not know how to serialize
a Regexp object. Fixes #3798.

To verify the fix, run the steps for issue #3798 and ensure that the module
options are returned instead of a backtrace. Also, ensure that the module
continues to work as expected:

```
$ ./msfconsole -q
msf > use auxiliary/scanner/http/scraper
msf auxiliary(scraper) > info

       Name: HTTP Page Scraper
     Module: auxiliary/scanner/http/scraper
    License: Metasploit Framework License (BSD)
       Rank: Normal

Provided by:
  et <et@metasploit.com>

Basic options:
  Name     Current Setting               Required  Description
  ----     ---------------               --------  -----------
  PATH     /                             yes       The test path to the page to analize
  PATTERN  (?i-mx:<title>(.*)<\/title>)  yes       The regex to use (default regex is a sample to grab page title)
  Proxies                                no        Use a proxy chain
  RHOSTS                                 yes       The target address range or CIDR identifier
  RPORT    80                            yes       The target port
  THREADS  1                             yes       The number of concurrent threads
  VHOST                                  no        HTTP server virtual host

override default attr for OptRegexp
Description:
  Scrap defined data from a specific web page based on a regular
  expresion

msf auxiliary(scraper) > set RHOSTS lwn.net
RHOSTS => lwn.net
msf auxiliary(scraper) > set RHOSTS 72.51.34.34
RHOSTS => 72.51.34.34
msf auxiliary(scraper) > set VHOST lwn.net
VHOST => lwn.net
msf auxiliary(scraper) > run

[*] [72.51.34.34] / [Welcome to LWN.net [LWN.net]]
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
```
Land #4453, OptRegexp default attr fix
Update from upstream