Fixed a minor issue with the 0.80 release notes
Fix coercion for variable arity functions

Arguments were not being coerced if the first argument was not a super
type of the later arguments.
Implemented LEAST function with variable number of arguments.
Add docs for arbitrary() and release notes for 0.88
Update airbase to 29-SNAPSHOT

This makes the dependency plugin compatible with Java 8
Remove unused methods
Remove getter functions from ByteCodeExpression
Remove getter functions from JmxColumnHandle
Remove getter functions from JmxRecordSetProvider
Remove getter functions from QueryInfo
Remove getter functions from SqlStageExecution
Remove getter functions from SqlTask
Remove getter functions from StageInfo
Remove getter functions from TaskInfo
Remove getter/predicate functions from HeartbeatFailureDetector
Remove getter functions from ColumnHandle
Remove getter functions from FunctionInfo
Remove getter functions from MetadataUtil
Remove getter functions from ParametricFunctionUtils
Remove getter functions from Partition