fix: escape spaces in bin

[wobww]

Air was unable to run my binary because there were spaces in the path, the same issue is described here -> #546.

This change fixes it by escaping spaces in the path at config setup time.

[ainsleyclark]

Hi, will this be merged soon? Noticed this problem when having a space in the folder name.

[osteensco]

Bumping this as I just started trying to use air and had the same issue that this PR solves.

[makiuchi-d]

Seems to be a duplicate of #199.
And, it doesn't work on windows.

[osteensco]

Seems to be a duplicate of #199. And, it doesn't work on windows.

I submitted #646, which should work on windows as well.