Original issue https://github.com/jackc/pgtype/issues/68
This crash occurred in the recursive assignment system used to support
multidimensional arrays.
This was fixed in 9639a69d451f55456f598c1aa8b93053f8df3088. However,
that fix incorrectly used nil instead of an empty slice.
In hindsight, it appears the fundamental error is that an assignment to
a slice of a type that is not specified is handled with the recursive /
reflection path. Or another way of looking at it is as an unexpected
feature where []T can now be scanned if individual elements are
assignable to T even if []T is not specifically handled.
But this new reflection / recursive path did not handle empty arrays.
This fix handles the reflection path for an empty slice by allocating an
empty slice.
Adds array support - previously only slices were supported.
Adds new test cases for multidimensional arrays and slices.
All previous test cases are unmodified and passed (fully backwards compatible).
Removes hard-coded type conversions for arrays, instead now relies on the type support of the array element's type conversion support.
Less maintenance for arrays, new type conversions are automatically supported when array's element gains new type support.
Simplifies typed_array_gen.sh generator script by removing the hard-coded single-dimensional types for arrays.
Only typed_array.go.erb and typed_array_gen.sh have been changed + 1 new auxiliary function in array.go file + additional tests in test files for each array. Other changes are from generated code.
