Draft for str tests.
Second draft of test involving n^2 addition of data dimension types to datashapes.
Fixed variable syntax error.
option types on records when mixed with nulls
lowest_common_dshape recurses into Records
move record uniting from lowest_common_dshape to unite_base
speed up test_dshape_into_repr test
Merge branch 'tests'
remove toolz import
Merge pull request #94 from mrocklin/lowest-common-dshape-on-records

Datashape uniting within nested records
dimensions works on option types
unite_base works on all nulls
isscalar predicate
Merge pull request #96 from mrocklin/discovery-fixes

Discovery fixes
add isscalar to predicates.__all__
Merge branch 'discovery-fixes'
add isunit predicate, improve _dimensions
integers are valid dimensions
add isrecord predicate
add iscollection predicate