Adaptative (local) abstol to validate integration (#112)

* Add adaptive (abstol) keyword for validated_integ

* Add keyword absorb

* Tests validated_integ2 with pendulum

* Cleanup validated_integ2. Add method iscontractive

* Fix deprecations

* Give info when tests fail (validated_integ.jl)

* Reorganize tests for validated integration methods

* Fix errors in flowpipe and use broadcasting

* Avoid Random in tests

* Flexible minabstol with default value

* Exit integration if the validation failed
... with warnings

* Allow incrementing (local) abstol