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.
Because reading a record type requires the decoder to be able to look up oid
to type mapping and types such as hstore have types that are not fixed between
different PostgreSQL servers it was necessary to restructure the pgtype system
so all encoders and decodes take a *ConnInfo that includes oid/name/type
information.
