Rename SetId() to setId()
Hopefully fixed a bug in the pact compiler for branching plans:
	- added a test case provided by Anja Kunkel from HU Berlin
	- my understanding of the bug is the following: During a check if additional pipeline breakers are necessary,
	the compiler checks for the LocalStrategy of a SinkJoinerPlan. The SinkJoinerPlan is a "fake" plan element to group multiple output sinks into one sink (the compiler assumes one root node, this is why a "fake" plan node is required).
	The local strategy of SinkJoinerPlan is initialized as NONE, which means that we just pass through the elements (which makes sence since we are talking about a sink) The initialization of a NONE-local strategy assumes only one input, not two.
	I replaced the LocalStrategy with BINARY_NO_OP, which is a NONE for two input.
	The compiler is now able to do its pipline breaker checks.
Merge pull request #89 from rmetzger/gith_compiler_bug2

Pact Compiler fix+testcase for SinkJoinerPlanNode