Update password field length in db.

Blowfish hashes generated by password_hash() are 60 chars long, moreover
PHP manual recommends using length 255 to be future proof.
Merge pull request #1429 from ADmad/3.0-auth

Update password field length in db.
Add FlashComponent and FlashHelper docs
Add namespace directives, add missing underscore
[fr+ja+pt+sr] follow #1429

Update password field length in db.
Update plugins.rst
Update plugins.rst
Merge pull request #1433 from Agence-MMK/patch-1

Update plugins.rst
Remove flash stuff from session docs, use Flash classes in examples
Added information about new plugin structure and clarifying how to use the autoloader option
Updating more paths
Merge pull request #1434 from cakephp/3.0-plugin-changes

Added information about new plugin structure and clarifying how to use t...
Merge pull request #1430 from bcrowe/3.0-flash

3.0 - Add FlashComponent and FlashHelper docs
Update migration guide for FlashComponent/FlashHelper.

Remove docs for non-existing SessionHelper methods.
Fix syntax error.

Closes cakephp/cakephp#3753
Move note location in flash helper for consistency with the component
[fr] follow 93c0542

Remove flash stuff from session docs, use Flash classes in examples
[fr] Follow #1430

3.0 - Add FlashComponent and FlashHelper docs
[fr] follow d72e897

Fix syntax error.
[fr] follow 112c864

Update migration guide for FlashComponent/FlashHelper.