Fixed broken NULL pointer check.
Fixed uninitialized value.
Fixed uninitialized values in case of error return.
Fixed uninitialized value.
Fixed missing NULL pointer check.
Fixed memory leak.
Fixed memory leak.
Fixed missing declarations.
xfreerdp: use login name if no user name was set

If no user name is set with /u:.. use the login name of the current user will be
used as user name.
xfreerdp: clean up AuthenticationOnly

* removed dead code path: user name is always set now
* update message if no password was set
nego: print message when bypassing gateway

When "detect" is used as gateway usage method (which is the default)
it is tried to by-pass gateway connection for local hosts.
The detection might take some time therefore print a message that people
are aware that a detection is tried.

Fixes #2171
channels/urbdrc: fix segfault

Fix segmentation fault in urbdrc_main.c caused by missing memset.
Fix cleanup of RDPEI server-side channel
Merge pull request #2268 from hardening/rdpei_cleanup_fix

Fix cleanup of RDPEI server-side channel
Initializing ServerHostname string now with 0
Merge pull request #2272 from akallabeth/ipv6_parser_fix

Fixed conversion of IPv6 to ServerHostname
Merge pull request #2265 from TaGUNil/master

Fix segmentation fault in URBDRC
Merge pull request #2262 from bmiklautz/misc_fixes

Misc fixes
Merge pull request #2261 from akallabeth/more_memleak_fixes

More warning and memleak fixes
Standard RDP Security Layer Levels/Method Overhaul

[MS-RDPBCGR] Section 5.3 describes the encryption level and method values for
standard RDP security.

Looking at the current usage of these values in the FreeRDP code gives me
reason to believe that there is a certain lack of understanding of how these
values should be handled.

The encryption level is only configured on the server side in the "Encryption
Level" setting found in the Remote Desktop Session Host Configuration RDP-Tcp
properties dialog and this value is never transferred from the client to the
server over the wire.
The possible options are "None", "Low", "Client Compatible", "High" and
"FIPS Compliant". The client receices this value in the Server Security Data
block (TS_UD_SC_SEC1), probably only for informational purposes and maybe to
give the client the possibility to verify if the server's decision for the
encryption method confirms to the server's encryption level.
The possible encryption methods are "NONE", "40BIT", "56BIT", "128BIT" and
"FIPS" and the RDP client advertises the ones it supports to the server in the
Client Security Data block (TS_UD_CS_SEC).
The server's configured encryption level value restricts the possible final
encryption method.
Something that I was not able to find in the documentation is the priority
level of the individual encryption methods based on which the server makes its
final method decision if there are several options.
My analysis with Windows Servers reveiled that the order is 128, 56, 40, FIPS.
The server only chooses FIPS if the level is "FIPS Comliant" or if it is the
only method advertised by the client.

Bottom line:
* FreeRDP's client side does not need to set settings->EncryptionLevel
(which was done quite frequently).
* FreeRDP's server side does not have to set the supported encryption methods
list in settings->EncryptionMethods

Changes in this commit:

Removed unnecessary/confusing changes of EncryptionLevel/Methods settings

Refactor settings->DisableEncryption
* This value actually means "Advanced RDP Encryption (NLA/TLS) is NOT used"
* The old name caused lots of confusion among developers
* Renamed it to "UseRdpSecurityLayer" (the compare logic stays untouched)

Any client's setting of settings->EncryptionMethods were annihilated
* All clients "want" to set all supported methods
* Some clients forgot 56bit because 56bit was not supported at the time the
code was written
* settings->EncryptionMethods was overwritten anyways in nego_connect()
* Removed all client side settings of settings->EncryptionMethods
The default is "None" (0)
* Changed nego_connect() to advertise all supported methods if
settings->EncryptionMethods is 0 (None)
* Added a commandline option /encryption-methods:comma separated list of the
values "40", "56", "128", "FIPS". E.g. /encryption-methods:56,128
* Print warning if server chooses non-advertised method

Verify received level and method in client's gcc_read_server_security_data
* Only accept valid/known encryption methods
* Verify encryption level/method combinations according to MS-RDPBCGR 5.3.2

Server implementations can now set settings->EncryptionLevel
* The default for settings->EncryptionLevel is 0 (None)
* nego_send_negotiation_response() changes it to ClientCompatible in that case
* default to ClientCompatible if the server implementation set an invalid level

Fix server's gcc_write_server_security_data
* Verify server encryption level value set by server implementations
* Choose rdp encryption method based on level and supported client methods
* Moved FIPS to the lowest priority (only used if other methods are possible)

Updated sample server
* Support RDP Security (RdpKeyFile was not set)
* Added commented sample code for setting the security level