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
Fix some typos in AR- CHANGELOG, tests, method doc. fixed
Fix broken ActionController#action_missing

A recent change introduced the assumption that all controller actions
are known beforehand, which is not true when using action_missing.
Fix a typo
Merge pull request #9825 from rShetty/patch-1

Fix a typo
Merge pull request #9821 from vipulnsward/fix_typos_in_AR

Fix some typos in AR- CHANGELOG, tests, method doc. fixed
Properly named variable inside block

Closes #9824.
Removed unnecessary block
Merge pull request #9833 from choudhuryanupam/fix_active_schema_test

Removed unnecessary block
Tweak exception message to avoid giving potentially misleading suggestions
Revert "default the reaping frequency to 10 seconds"

mysql can't handle a parallel thread pinging the connection, so we can
get wrong results or segvs

This reverts commit 7cc588b684f6d1af3e7fab1edfa6715e269e41a2.
use `connect_poll` on pg so that reaping does not hurt the connection
Tidying up some require : removing useless sort and homogenizing with the rest of the code the wat the includes are done
Don't generate a scaffold.css if no-assets
Update other counter caches on destroy
Merge pull request #9837 from kjg/no_scaffold_css_when_no_assets

Don't generate a scaffold.css when --no-assets is specified
Merge pull request #9802 from newsline/fix-broken-action-missing

Fix missing action_missing

Conflicts:
	actionpack/CHANGELOG.md
Merge pull request #7706 from iangreenleaf/multiple_counter_caches

Update other counter caches on destroy
Fix copy table index test; Change == to ! on false in travis.rb