Clarified Containable filtering limitations

It isn't clear when using containable that an INNER JOIN isn't happening when filtering by a deeper level association, when it really is only affecting the subquery. I added an explanation and an example.
Further clarification

Added an example to return the expected results.
Temporary fix for missing pdf file
Remove unicode bytes that are blowing up PDF generation

pdflatex does not like these bytes.
REmoving characters that are killing PDF generation
Merge pull request #740 from derekperkins/patch-1

Clarified Containable filtering limitations
Move param() to the correct class.
Update html.rst

Clarify how to use named parameters in the "link" method of HTMLHelper.
Merge pull request #754 from NOSLOW/patch-1

Update html.rst
Breaking too long line
Update Model/Behavior callback documentation to be truthful.
Merge pull request #756 from bar/update-callbacks

Update Model/Behavior callback documentation to be truthful.
Added a file copied from original.
Updated .gitignore temporarily

To ignore PhpStorm settings
Translating...
Done.
Rollback .gitignore
Fixed code example, fixes #144


https://cakephp.lighthouseapp.com/projects/43067/tickets/144
Infinity looping bug

Whenever Cache lost the session data and Database has a copy of the expired data, ComboSession will not be able to destroy the expired session from Database and hence infinity looping happens (CakeSession rejected the data and attempted to destroy-start-destroy-start...). We solved this by modifying this code to make it deleting them from both Cache and Database regardless if Cache succeeded or not.
Update rss.rst

fixed error in sample code, $bodyText should be $post['Post']['body'] on line 155.  Or we could set $bodyText = $post['Post']['body'] above this line.