v0.7.0

(breaking) groupby and groupreduce now select all but the grouped columns (as opposed to all columns) (#120)
(feature) usekey=true keyword argument to groupby will cause the grouping function to be called with two arguments: the grouping key, and the selected subset of records. (#120)
(breaking) leftjoin and outerjoin, operations don't speculatively create DataValueArray anymore. It will be created if there are some keys which do not have a corresponding match in the other table. (#121)
(feature) Not, Join, Between and Function selectors have been added.

v0.8.0

(breaking) Uses new redisigned version of OnlineStats
- (breaking) Does not wrap OnlineStats in Series wrapper. (IndexedTables.jl#149) this means m = reduce(Mean(), t, select=:x) will return a Mean object rather than a Series(Mean()) object. Also value(m) == 0.45 for example, rather than value(m) == (0.45,)
(feature) - view works with logical indexes now (IndexedTables#134)

(breaking) Missing values represented as Union{T,Missing} rather than DataValue.

(breaking) Support for both Missing and DataValue representations of missing data.
- Defaults to Missing. functions that can create missing values have been given a missingtype = Missing keyword argument.