DRILL-643: Fix ByteBuf allocation in o.a.d.exec.vector.ValueHolderHelper.getVarCharHolder()
DRILL-644: Fix char length and position calculation for UTF-8 strings in StringFunctionUtil
DRILL-645: Correct string encodings in code template
DRILL-381: Implement SYSTEM and SESSION options.
DRILL-219: Math Trigonometric functions
DRILL-577: Two way implicit casts