abstract input value extraction, and add AutoForm.inputValueHandlers to support defining override functions for value extraction
move events to a separate file
document custom input handlers
update toc
more tweaks of array field handling; fixes #208
modify input atts only rather than actual hash; fixes #206
Add beginSubmit and endSubmit hooks; fixes #201
pass through `id` attribute from afDeleteButton; fixes #194
update readme
Merge remote-tracking branch 'upstream/master'