i found a bug where you were using a variable "obj" that wasn't defined

In threaded applications, if the user does not explictly create a new 
event loop then one does not exist.

* Fix strftime format string

Lines 28 and 29 that were using `.strftime('%s')` where it should be written as `.strftime('%S')`. This error would make twint fail with an `Invalid format string` when using time-related configurations like `Since` and `Until`.

* Change strftime to timestamp

As we are looking for the timestamp version of the provided date/time string, using `timestamp()` should be more straightforward and shouldn't create any incompatibility issues as twint already requires Python >= 3.6

Enables twint to work with Flask

Select the working of the workaround's UA only for tweets, for followers/following use the old method that still works