Improvements
FormBuilder::checkbox can't be checked without session

If the value of FormBuilder::session is null, it’s not possible to set
a checkbox to checked.
Test checkbox without session.
Stashing limit/offset query values before performing total pagination count

Some database engines return zero, when using the count aggregate on a query with limit and offset. Just followed the same pattern for stashing the 'orders' clause before performing a count on the query, and adding back to the query when done.
Pivot updates recorded only if something updated
Fix associate on MorphTo
Merge pull request #4249 from jarektkaczyk/4.1-fix-associate-on-morphTo

Fix associate on MorphTo relation
Fix order.
Merge pull request #4242 from jmshelby/4.1

Stashing limit/offset clause before performing total pagination count
Cleaning up a lot of code.
Merge pull request #4230 from ironkeith/4.1

[4.1] FormBuilder::checkbox can't be checked without session
Merge pull request #4227 from JamShady/pull-request/pivot-update-only-includes-updated-items

Pivot updates recorded only if something updated
Use comment.
Merge pull request #4222 from GrahamCampbell/4.1-stuff

[4.1] Improvements
Fixing conflicts and merge.