Merge rails4 branch into master

This pull request merges current rails4 branch into master with tag v1.4.3.

When this pull request merged, master branch just supports Rails 4. To compatibility with Rails 3.2 and lower version of Rails, you can checkout tag 'v1.4.3'.

```ruby
$ git checkout master
Already on 'master'
$ git checkout -b master_merges_rails4_1st
Switched to a new branch 'master_merges_rails4_1st'
$ git merge rails4
Updating bdbdbdd..f15de84
Fast-forward
 Gemfile                                            |    6 +-
 activerecord-oracle_enhanced-adapter.gemspec       |    4 +-
 .../oracle_enhanced_activerecord_patches.rb        |   41 --
 .../connection_adapters/oracle_enhanced_adapter.rb |  368 ++++++++++++++++---
 .../oracle_enhanced_base_ext.rb                    |  121 ------
 .../oracle_enhanced_column_dumper.rb               |   55 +++
 .../oracle_enhanced_context_index.rb               |   17 +-
 .../connection_adapters/oracle_enhanced_dirty.rb   |   11 +-
 .../oracle_enhanced_procedures.rb                  |  395 ++++++++------------
 .../oracle_enhanced_schema_definitions.rb          |   28 +-
 .../oracle_enhanced_schema_dumper.rb               |   52 +--
 .../oracle_enhanced_schema_statements.rb           |   89 +++--
 .../connection_adapters/oracle_enhanced_tasks.rb   |   17 -
 .../oracle_enhanced_adapter_spec.rb                |   79 +----
 .../oracle_enhanced_context_index_spec.rb          |  196 +++++-----
 .../oracle_enhanced_data_types_spec.rb             |    6 +-
 .../oracle_enhanced_dbms_output_spec.rb            |    6 +-
 .../oracle_enhanced_procedures_spec.rb             |   16 +-
 .../oracle_enhanced_schema_dump_spec.rb            |  111 +++---
 .../oracle_enhanced_schema_statements_spec.rb      |   14 +-
 .../oracle_enhanced_structure_dump_spec.rb         |    7 +-
 spec/spec_helper.rb                                |   79 ++---
 22 files changed, 851 insertions(+), 867 deletions(-)
 delete mode 100644 lib/active_record/connection_adapters/oracle_enhanced_activerecord_patches.rb
 delete mode 100644 lib/active_record/connection_adapters/oracle_enhanced_base_ext.rb
 create mode 100644 lib/active_record/connection_adapters/oracle_enhanced_column_dumper.rb
 delete mode 100644 lib/active_record/connection_adapters/oracle_enhanced_tasks.rb
$
```