Added Indeterminate Progress Mode

[oduwa]

Indeterminate mode can be activated and deactivated by calling [radialView setIsIndeterminateProgress:YES] and [indeterminateRadialView setIsIndeterminateProgress:NO] respectively.

I used MDRadialProgress in a project of mine and wanted to convey an indeterminate state where an activity has not begun but preparations are being made. I noticed this feature did not exist so I added it.

Below is an example of it in action.

[mdinacci]

Hi @oduwa

this is a fantastic contribution, thank you very much ! I'll merge it and during the week I'll find some time to release a new version and update it on Cocoapod.

[oduwa]

@mdinacci it was my pleasure, its a really cool project.