Have ^C throw InterruptException

[Keno]

In general ^C throws InterruptException. The only reason this doesn't
happen in TerminalMenus is because we enable raw mode which makes ^C
just another key sequence. I think it is more coherent to make this
throw an InterruptException as it would in non-raw parts of code.
If the calling code wants to handle this, it can catch the exception.

Fixes JuliaPackaging/BinaryBuilder.jl#35

[codecov-io]

Codecov Report

Merging #10 into master will decrease coverage by 0.03%.
The diff coverage is 66.66%.

@@            Coverage Diff            @@
##           master     #10      +/-   ##
=========================================
- Coverage   53.63%   53.6%   -0.04%     
=========================================
  Files           6       6              
  Lines         220     222       +2     
=========================================
+ Hits          118     119       +1     
- Misses        102     103       +1

Impacted Files	Coverage Δ
src/AbstractMenu.jl	39.02% <66.66%> (+0.27%)	⬆️

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[nick-paul]

I will merge this and then tag a release for v0.0.4

[nick-paul]

@Keno Note: I just added (6254c9d) a configuration option to change the behavior of ^C back to the way is was before (returning -1 or an empty set) if needed. I think you are right in saying that throwing the InterruptException() is generally more coherent behavior so I made it the default option.