Exiting with 1 when Exception::getCode() returns non-integer values.

From php.net/exception.getcode
> Returns the exception code as integer in Exception but possibly as other type in Exception descendants (for example as string in PDOException).
Merge pull request #3809 from renan/2.5-non-integer-exception-code

Exiting with 1 when Exception::getCode() returns non-integer values.
cs correction
Fix identifier typos
Fix more doc block errors in lib/
Tidy up and simplify travis.yml file.
Merge pull request #3829 from cakephp/api-doc-fixes

API doc fixes
Add pluralization rule for "stadia".

Refs #3830
Merge pull request #3832 from ADmad/2.5-inflector

Add pluralization rule for "stadia" to uninflected list.
Revert "No truncate when drop table."
Relax email validation rules even more.

While filter_var() allows a number of email addresses that
Validation::email() does not, it misses out of email address that
contain IDN host names, and unicode mailboxes. Both of these are
generally deliverable, and should be permitted. filter_var() also fails
on local mailboxes like `root@localhost` which is useful in the context
of cron jobs.

Fixes #3742
Fix failing test.

CakeEmail now has a default validation pattern.

Refs #3742
Merge pull request #3840 from cakephp/issue-3742-relax-email

Relax email validation rules even more.

Fixes #3742
Merge pull request #3838 from cakephp/revert-3646-no-truncate-fixture

Revert "No truncate when drop table."

Not truncating tables when they are created causes a number of 
issues in ControllerTestCases as indicated by the comments in #3646 post merge.
Fix for CakeResponse::sharable() header to include private caches
Fix additional missing API doc tags.
Make PHPCS build passing again.
Update code examples to be consistent with other docs.
Remove mention of Role/default as it doesn't exist.

The default role merging was removed in
3abfaeecf30b845ac3a309f011bc460222a923b4 and shouldn't be mentioned in
the docs.

Fixes #3871
Correct doc blocks according to cs guidelines.
Remove superfluous empty lines.