updated tests
removed xAtCol, added tests.
updated xExplode tests
added new (failing) tests
updated more tests
updated more tests.
added tests for xTo_
flatten now removes names.
renamed xIsMember, xNotMember to x_In
fixed misreference to indices
fixed missing dependency
updated xDeepMap test.
removed xAtCol, fixed several bugs.
Merge branch 'develop' into releases