Fill in documentation of standard types defined by datashape
Add first draft of datetime types
Adopt ICU library's "universal time scale" for storage, add units type
Add an example to the strided dimension description
Add some comments on type variables
Indicate that bignum vs bigint needs to be decided later
Merge pull request #36 from mwiebe/datetime_design

datetime type design
Add types timetz and datetimetz, with the time zone in the data
Merge pull request #37 from mwiebe/datetime_design

Add types timetz and datetimetz, with the time zone in the data