incorrect value for 'last' in validatio rules

As said in documentation:
"If set to true and the current rule does not validate, the current validation error message is then returned and all following rules for the current field will not be checked."
Merge pull request #3879 from mohsen-ekhtiari/patch-1

incorrect value for 'last' in validatio rules
Backport changes from cakephp/cakephp#3959 to 1.3

Backport race condition fixes from 2.x to 1.3. This is a severe enough
issue that it warrants a fix.

Refs #3857
Fix failing tests.

These tests were failing as integers were not being quoted as strings
which is expected for me at least.
Bump version to 1.3.20
Issue on empty param

The function returns "31/12/1969 21:00:00" when pass empty date param.
Fix TimeHelper returning 1969 on invalid dates.

Instead of returning 1969, TimeHelper should return the invalid date,
and if that is missing '' should be returned.

Fixes #4294
Merge branch 'issue-4294' into 1.3
Removed all occurences of crc32 in dbo_source as a cache key,
 which is not only a stupid idea but should be actually considered a bug!
It does collide with a .1% propability for every 1.6mio queries processed
(which is not to uncommon in a shell process).
Removed crc32() because of *very* common collisions occuring.

Does not touch any of the exposed stuff and will not break anything
else (except you know of a collision within crc32 already and make
"use" of it - which can only be malcious.)

Has already been "fixed" in the 2.x branch.
Merge pull request #4368 from hmic/1.3-dbo_source-NO-crc32

1.3 dbo source no crc32
Vendors equals include path constant.

This allows to have the `cake` directory placed inside the root
`vendors` directory at `vendors/cake`.
Introduce HTML5 attributes.
Introduce HTML5 form inputs.
Use minimal markup for HTML5 where possible.
Manually include media view during dispatch.

In some rare cases this caused problems due to `import()` not being
bootstrapped already.
Remove cache limiter to allow better manual control.
Remove P3P header, allows for better manual control.
Adding a backtrace to the `logQuery()` method.
Default translation functions to return.