Remove RecordBatch from setup method of DrillFunc interface

Drill UDFs currently are exposed to too much system state by receiving a reference to a RecordBatch in their setup method. This is not necessary as all of the schema change triggered operator functionality is handled outside of UDFs (the UDFS themselves are actually required to define a specific type they take as input, except in the case of complex types (maps and lists)). The only remaining artifact left from this interface is the date/time functions that ask for the query start time or current timezone. This can be provided to functions using a new injectable type, as DrillBufs are provided to functions currently. For more info read here: http://mail-archives.apache.org/mod_mbox/drill-dev/201501.mbox/%3CCAMpYv7AC_-9u4iRZ+5fxoenzBOJCTovJronn0qri4BQZf535Qw@mail.gmail.com%3E