support for less than 4 sources

[byt3h3ad]

currently opening less than 4 sources leaves a blank space for the fourth space, which looks ugly. making it dynamic such that it adjusts the space will look much cleaner.
(what im talking about)

[medyo]

It's done on purpose to keep each card in a good shape.
There are some cases where flexible width won't work like having 1 card. it'll occupy the full screen width.
What do you think?

[lennarto]

I would make the number of columns adjustable :)

#143