Maintain proleptic gregorian in Time#advance

Time#advance uses Time#to_date and Date#advance to calculate a new date.
The Date object returned by Time#to_date is constructed with the assumption
that the Time object represents a proleptic gregorian date, but it is
configured to observe the default julian calendar reform date (2299161j)
for purposes of calculating month, date and year:

  Time.new(1582, 10, 4).to_date.to_s           # => "1582-09-24"
  Time.new(1582, 10, 4).to_date.gregorian.to_s # => "1582-10-04"

This patch ensures that when the intermediate Date object is advanced
to yield a new Date object, that the Time object for return is contructed
with a proleptic gregorian month, date and year.
Fix stream closing when sending file with `ActionController::Live` included.

Fixes #12381
mem_cache_store requires dalli, so only accept dalli/client

:mem_cache_store require dalli, rescue Dalli exceptions, and follow Dalli API.
Memcached gem, for instance, doesnt work anymore, as the API are different.

As we already require one client, we should make sure that client works, and not accept others, and if someone wants to use another memcache client they can write their own store adapter.
Minor typo fix [ci skip]
Raise if MemCacheStore doenst receive a Dalli obj

:mem_cache_store should receive a list of hosts or a dalli client,
otherwise raise it.
Also adding a changelog.
Merge pull request #13583 from arthurnn/mem_cache_store_fix

mem_cache_store requires dalli, so only accept dalli/client
Change all "can not"s to the correct "cannot".
Merge pull request #13584 from tjschuck/cannot_cannot_be_can_not

Change all "can not"s to the correct "cannot"
Add deprecation I accidentally missed
Fix mergefail in changelog

The line was duplicated
Fixed  documentation. [ci skip]
Merge pull request #13587 from kud86/change_truncate_examples

Fixed truncate documentation. [ci skip]
provide correct example of `datetime_select` helper [ci skip]
Add preview_path to autoload_paths in after_initialize

Only config.autoload_paths is frozen, so add the preview_path
to ActiveSupport::Dependencies.autoload_paths directly in an
after_initialize block. Also protect against a blank preview_path
being added to autoload_paths which can cause a serious slowdown
as Dir[] tries to load all *_preview.rb files under /

Fixes #13372
Merge pull request #13590 from kuldeepaggarwal/fix-date-helper-doc

provide correct example of `datetime_select` helper [ci skip]
Use a custom route vistor for optimized route generation

Using a Regexp to replace dynamic segments in a path string is fraught
with difficulty and can lead to odd edge cases like #13349. Since we
already have a parsed representation of the path it makes sense to use
that to generate an array of segments that can be used to build an
optimized route's path quickly.

Tests on a simple route (e.g. /posts/:id) show a speedup of 35%:
https://gist.github.com/pixeltrix/8261932

Calculating -------------------------------------
    Current Helper:       5274 i/100ms
    New Helper:           8050 i/100ms
-------------------------------------------------
    Current Helper:     79263.6 (±3.7%) i/s -     395550 in   4.997252s
    New Helper:        153464.5 (±4.9%) i/s -     772800 in   5.047834s

Tests on a more complex route show even an greater performance boost:
https://gist.github.com/pixeltrix/8261957

Calculating -------------------------------------
    Current Helper:       2367 i/100ms
    New Helper:           5382 i/100ms
-------------------------------------------------
    Current Helper:     29506.0 (±3.2%) i/s -     149121 in   5.059294s
    New Helper:         78815.5 (±4.1%) i/s -     398268 in   5.062161s

It also has the added benefit of fixing the edge cases described above.

Fixes #13349
Simplify arg parameterization
Show full route constraints in error message

When an optimized helper fails to generate, show the full route constraints
in the error message. Previously it would only show the contraints that were
required as part of the path.

Fixes #13592
Unique the segment keys array for non-optimized url helpers

In Rails 3.2 you only needed pass an argument for dynamic segment once so
unique the segment keys array to match the number of args. Since the number
of args is less than required parts the non-optimized code path is selected.
This means to benefit from optimized url generation the arg needs to be
specified as many times as it appears in the path.

Fixes #12808
Switched to use `display:none` in extra_tags_for_form method.

The use of `display:inline` with the content_tag call in the
extra_tags_for_form method potentially causes display issues with some
browsers, namely Internet Explorer. IE's behaviour of not collapsing
the line height on divs with ostensibly no content means that the
automatically added div containing the hidden authenticity_token, utf8
and _method form input tags may interfere with other visible form
elements in certain circumstances. The use of `display:none` rather
than `display:inline` fixes this problem.

Fixes #6403