Add match parameter to transformNull

The match parameter is optional and takes a series.  If it is
specified, only where the match series has non-Null values will
Nulls in the target metric be replaced with the default value.
Added delay function.
Merge branch 'master' into delay
Fixed delay collection usage.
Handle transformNulls missing match, empty series lists gracefully.
Handle missing divisor series in divideSeries gracefully.
Added match test transformNulls
Added test for delay function.
Merge branch 'master' into delay
Fixed transformNull empty match parameter.
Lint fixes.
Merge remote-tracking branch 'baxter/transform_null_match_series'
Merge remote-tracking branch 'baxter/delay'
Merge remote-tracking branch 'baxter/divide_fixes'