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
Add ProjectSend Arbitrary File Upload module
Move it to a common method
one line if statement
Update from upstream
Do style cleaning on metadata
Use single quotes when possible
Clean exploit method
Clean get_restart_commands
Check payload
Do minor c code cleanup
Beautify restart_command creation
Land #3695, @jakoblell linux desktop privilege escalation

* through screensavers / policykit user component hijacking
Do minor cleanup
Land #4459, @bcoles's ProjectSend Arbitrary File Upload module