Add logback and SLF4J 1.7
 - SLF4J is included by Thrift
 - logback (or similar) is needed by SLF4J
 - logback 1.0.13 requires SLF4J 1.6 or newer
Rationalise POMs slightly
Add RunnerServer and tests to prove clients can connect
Rename remote -> executor
Add SLF4J 1.7.5 IDEA library xml
Add evil hack to get ExecutorServerTest passing more reliably