Add support for parsing autocommit clause
Add autocommit information to AbstractQuery by introducing new AutocommitQuery

o Introduce PipeInfo in ExecutionPlanBuilder to track this info as a replacement for PipeAndIsUpdating
Evaluate expression to compute autocommit batch size

o Refactored QueryState to be able to instantiate it without collecting statistics
Reject negative autocommit batch size and use default size for null expressions
Merge remote-tracking branch '2.0-maint' into 2.0-autocommit

Conflicts:
	community/cypher/cypher-compiler-2.0/src/main/scala/org/neo4j/cypher/internal/compiler/v2_0/parser/Query.scala
Move semantic checking of autocommit to the AST
Move AUTOCOMMIT to the beginning of a Query
Move semantic check of autocommit to AST from ExecutionPlanBuilder
Refactoring of collecting statistics on QueryState
Added commitAndRestartTx to QueryContext
Merge branch '2.0-autocommit' of github.com:boggle/neo4j into 2.0-autocommit
Fix license headers
Fix warning: Union is now a sealed trait