Add PK constraint on bigserial ID columns on postgres adapter

https://github.com/rails/etagger/pull/3

In #10410 it was noted that you can no longer create PK's with the
type of bigserial in PostgreSQL in 4.0.0.rc1. This is mostly
because the newer adapter is checking for column type with the
id column instead of just letting it pass through like it did
before.

Side effects:
You may just create a PK column of a type that you really don't
want to be your PK. As far as I can tell this was allowed in 3.2.X
and perhaps an exception should be raised if you try and do
something extremely dumb.

Allow fetching multiple values from the cache at once

Allow numbers in partial name for digesting

Instrument template compilation

Add failing test for template with number at the end

Use \w for RENDER_DEPENDENCY regex

Spacing

Add CHANGELOG entry

Confirm a record has not already been destroyed before decrementing counter cache

Conflicts:
	activerecord/CHANGELOG.md

use canonical #controller_path logic in controller test cases

counter cache

At present, calling destroy multiple times on the same record results
in the belongs_to counter cache being decremented multiple times. With
this change the record is checked for whether it is already destroyed
prior to decrementing the counter cache.

Fix bug in ActiveRecord::Sanitization#sanitize_sql_hash_for_conditions

Fixing CHANGLOG description

Remove extra line.

Remove blank lines.

fix failing test caused by 3771e4d5

See the comment in the rescue clause towards the top of the patch for the rationale.

raise IrreversibleMigration if no column given

fixes #10419

Following code should raise  IrreversibleMigration. But the code was
failing since options is an array and not a hash.

def change
  change_table :users do |t|
    t.remove_index [:name, :email]
  end
end

Fix was to check if the options is a Hash before operating on it.

remove unused variable

Add a simple API for fetching a list of entries from the cache, where
any missing entries are computed by a supplied block.

Speed up Hash#to_param by switching from #sort to #sort!

Fix typo in documentation comment [ci skip]

Check https://gist.github.com/vipulnsward/6aad158c06a22f931a71 to see the gains.

use nokogirisax as a backend

Most likely someone just forgot to change it during copying and
pasting test cases from nokigiri engine test.

Updated link to to GitHub article about ignoring files [ci skip]

- http://help.github.com/ignore-files redirects to https://help.github.com/articles/ignoring-files

Fix tests related to scaffolding generator with --assets=false switch

Added missing `require` to ActionView::LookupContext

Github -> GitHub [ci skip]

- f1805a69 Redefined 'test_scaffold_generator_no_assets' twice.
- Only the last instance of these three definitions of the same method
  was getting called when the tests were actually running.
- This commit changes names of this method so that all three
  definitions will be called
- scaffold.css is not generated by --assets=false switch.
- Test was expecting the presence of the file with --assets=false
- This issue was not discovered in f1805a69 because it was
  redefining the same method twice