PLAT-6840 Add noCopy constructor for ImmutableLocalDateDoubleTimeSeries
PLAT-6840 Replace noCopy() with withValues()
PLAT-6840 Optimise unionOperate() method if series share times
PLAT-6840 review comments
Merge pull request #248 from OpenGamma/topic/PLAT-6840

PLAT-6840 Add noCopy constructor for ImmutableLocalDateDoubleTimeSeries