Use the correct port for GoldSrc master servers

See koraktor/steam-condenser#218
Fixed Web API calls without key

See koraktor/steam-condenser#219
Implemented WebApi.getInterfaces()
DRYed up Web API tests
Add test for Web API without key
Updated logging to use slf4j and log4j

See koraktor/steam-condenser#182
Do not depend on slf4j-log4j directly

As a library, we should leave the decision for a logging framework to
the application developer.
Add a README note on logging
Merge branch 'issue-182'
Make RCON termination conditional

Only non-empty RCON replies will be accompanied by a termination
request. This will prevent timeouts during `changelevel` and similar
commands.

See koraktor/steam-condenser#221
Fix trailing whitespace
Version bump to 1.3.6
Merge branch '1.3-stable'

Conflicts:
	src/main/java/com/github/koraktor/steamcondenser/steam/community/WebApi.java
	src/main/java/com/github/koraktor/steamcondenser/steam/servers/MasterServer.java