IAP tracking requests now take an optional receipt data parameter which can be collected after an IAP completes, cancels, or fails due to IAP.
Example IAPHelper implementation upated to reflect this.
fixes some issues in the PHPublisherIAPTrackingRequest
adds a new controller to the example app for testing IAP requests directly
Change to preloading that makes it clear if content templates are loaded from network or cache.
minor copy edits

Such as periods.
links

anchors
Merge branch '1.12.1-release' into develop
more links
section reorg
more copy edits
more copy edits plua ignore edit
list type, misc
merge confict with Jesus
remove markers, spelling, link
review comments
markdown cleanup, edits. mini-toc
import, links to api section
active present
end style, jesus comments
generates lone-mtn request digests, unit tests
new error type