= Performance Enhancements

* The internal implementation of eager_graph has been made 75% to
  225% faster than before, with greater benefits to more complex
  graphs.

* Dataset creation has been made much faster (2.5x on 1.8 and 4.4x on
  1.9), and dataset cloning has been made significantly faster (40%
  on 1.8 and 20% on 1.9).

= Other Improvements

* Strings passed to setter methods for integer columns are no longer
  considered to be in octal format if they include leading zeroes.
  The previous behavior was never intended, but was a side effect of
  using Kernel#Integer.  Strings with leading zeroes are now treated
  as decimal, and you can still use the 0x prefix to treat them as
  hexidecimal.  If anyone was relying on the old octal behavior, let
  me know and I'll add an extension that restores the octal behavior.
  
* The identity_map plugin now works with the standard eager loading
  of many_to_many and many_through_many associations.
  
* Database#create_table! now only attempts to drop the table if it
  already exists.  Previously, it attempted to drop the table
  unconditionally ignoring any errors, which resulted in misleading
  error messages if dropping the table raised an error caused by
  permissions or referential integrity issues.

* The default connection pool now correctly handles the case where a
  disconnect error is raised and an exception is raised while
  running the disconnection proc.
  
* Disconnection errors are now detected when issuing transaction
  statements such as BEGIN/ROLLBACK/COMMIT.  Previously, these
  statements did not handle disconnect errors on most adapters.
  
* More disconnection errors are now detected.  Specifically, the ado
  adapter and do postgres subadapter now handle disconnect errors,
  and the postgres adapter handles more types of disconnect errors.
  
* Database#table_exists? now always issues a query to select from the
  table, it no longer attempts to parse the schema to determine the
  information on PostgreSQL and Oracle.

* Date, DateTime, and Time values are now literalized correctly on
  Microsoft Access.

* Connecting with the mysql adapter with an options hash now works if
  the :port option is a string, which makes it easier to use when the
  connection information is stored in YAML.

* The xml_serializer plugin now works around a bug in pure-Java
  nokogiri regarding the handling of nil values.

* Nicer error messages are now used if there is an attempt to call
  an invalid or restricted setter method.

* The RDocs are now formatted with hanna-nouveau, which allows for
  section ordering, so the Database and Dataset RDoc pages are
  more friendly.

= Backwards Compatibility

* If you call a Dataset method such as #each on an eager_graphed
  dataset, you now get plain hashes that have column alias symbol
  keys and their values. Previously, you got a graphed response with
  table alias keys and model values.  It's not wise to depend on the
  behavior, the only supported way of returning records when eager
  loading is to use #all.

* An error is now raised if you attempt to eager load via
  Dataset#eager a many_to_many association that includes an
  :eager_graph option.  Previously, incorrect SQL would have been
  generated and an error raised by the database.
  
* Datasets are no longer guaranteed to have @row_proc,
  @indentifier_input_method, and @identifier_output_method defined
  as instance variables.  You should be be using methods to access
  them anyway.

* Database#table_exists? on PostgreSQL no longer accepts an options
  hash.  Previously, you could use a :schema option.  You must now
  provide the schema inside the table argument (e.g. :schema__table).

* If you want to use the rdoc tasks in Sequel's Rakefile, and you are
  still using the hanna RDoc template with RDoc 2.3, you need to
  upgrade to using hanna-nouveau with RDoc 3.8+.
