Fix ActiveRecord locking column defaults not getting persisted

When partial inserts are enabled, overridden db defaults are ignored. This
results in locking columns having a nil value for new records if the db default
is null. This happens because the list of changed attributes for new records is
always assumed to be empty.

Solution: When a new record's default attributes are set, also initialize the
list of changed attributes by comparing current values against what's stored as
the column defaults in the database.
Raise an ArgumentError when a clashing named route is defined
Tweak exception message to avoid giving potentially misleading suggestions
Add version method to top level modules
remove references to *::VERSION, replace with *.version
Add Error#full_message test; Fix typos

Introduce test on Error#full_message for attribute with underscores; Fix
some typos
add changelog entry
Merge pull request #8501 from charliesome/version-to-s

Add #to_s method to VERSION modules
Ignore pkg folders
Merge pull request #9897 from robertomiranda/ignore-pkg-folders

Ignore pkg folders
Ignore all pkg folders (including also top level one)
Use jquery-rails from github (fix Gem::Version error)
Fix test: ActiveSupport.version is returning now a Gem::Version instead of a String
Add a method full_messages_for to the Errors class
Fix some typos
Fix update_version_rb task
Merge pull request #9901 from vipulnsward/fix_some_typos

Fix some typos
Merge pull request #9902 from robertomiranda/fix-release-task

Fix update_version_rb task
Use jquery-rails from github

completes https://github.com/rails/rails/commit/6f3f0f86332004fcee5c2f05d52bbff08c22f980
Updated docs due to removal of serializer accessor