Support for BottomSlideNotification

[gilescm]

Hi,

This PR covers the new implementation of #39 which removes references to SnackBar and updates implementation to use position which can be NotificationPosition.top or NotificationPosition.bottom.

[boyan01]

Thanks.

I run this pr in local and found a small problem... it seems that BottomSlideNotification has a addition top padding.

This extra padding is caused by this line of code.

overlay_support/lib/src/notification/overlay_notification.dart

Line 65 in 8aba967

bottom: false,

Maybe in the bottom notification mode, should we remove this TopPadding? Or do you have a better idea ?

[gilescm]

Oh good find! Sorry I should've noticed that before.

After some investigation the extra padding was also caused by SafeArea defaulting its parameter top=true. I've updated both bottom and top parameters so that the correct amount of padding is created for the two different positions of the notification, and bottom=false is maintained when using NotificationPosition.top.

[boyan01]

Looks Good To Me. Thank you very much for your contribution.

[gilescm]

Great thanks. No problem I'm very happy to contribute!

[EArminjon]

Hi !

When will be available this new version :) !

[boyan01]

@EArminjon 1.0.4 Published just now.