Use register_class_with_limit

Refer https://github.com/rails/rails/commit/111990513b20c045d4af08b20f07f98c7e2c0b92
Merge pull request #502 from yahonda/rails42_register_class_with_limit

Rails4.2 Use register_class_with_limit
Add Type::Raw type
Merge pull request #503 from yahonda/rails42_raw

Rails4.2 Add Type::Raw type
Don't type cast the default on the column
Merge pull request #504 from yahonda/rails42_default_string

Rails4.2 Don't type cast the default on the column
Rails 4.2 support emulate_booleans_from_strings and is_boolean_column?
Merge pull request #506 from yahonda/rails42_boolean

Rails 4.2 support emulate_booleans_from_strings and is_boolean_column?
Handle NUMBER sql_type as `Type::Integer` cast type
since Oracle database NUMBER datatype handles interger and decimal.
Merge pull request #509 from yahonda/rails42_decimal_without_scale

Rails 4.2 Handle NUMBER sql_type as `Type::Integer` cast type
Address ArgumentError: wrong number of arguments (1 for 2) at `quote_value`
Merge pull request #511 from yahonda/rails42_quote_value_text

Rails 4.2 Address ArgumentError: wrong number of arguments (1 for 2) at `quote_val...
Support OracleEnhancedAdapter.number_datatype_coercion for Rails 4.2
Merge pull request #512 from yahonda/rails42_number_datatype_coercion_float

Support OracleEnhancedAdapter.number_datatype_coercion for Rails 4.2
Remove redundant substitute index when constructing bind values

refer https://github.com/rails/rails/pull/17463
Merge pull request #517 from yahonda/rails42_substitute_at

Rails 4.2 Remove redundant substitute index when constructing bind values
Use Arel::Visitors::Oracle12 when Oracle server version is 12c
to use better top-N query support