Code cleanup and fix compatibility for ss 3.2 (do not merge just yet)

Here's a mega cleanup for 3.2. Still needs some more testing.

* Changed constructors to use Object::create syntax
* Updated all where and sql fragments to use filters where possible
* Fixed coding conventions
* Removed blank has_ones etc
* getCMSFields now uses beforeUpdateCMSFields instead of disabling extensions
* Removed TypoImport
* Fixed LandingPageFreshness
* Deprecated the callback on `BlogTree::Entries` method. Sneakily snuck in a $filters parameter with a bit of detection to see if it is used as a callback.

This needs to be reviewed and a 0.7 branch created for 3.1 compatibility prior to merge.