lots of internal reworking; move autoValue from C2 to SS
add defaultValue option
add `this.key` and `this.siblingField()` to `custom` validation context; fix #67
add `this.key` and `this.siblingField()` to `custom` validation context; fix #67
corrections and improvements to autoValue/defaultValue; defaultValues are now implemented as autoValues behind the scenes
another autovalue fix
bump version