Signals fix

[vlaaad]

Hi there!
First of all, ashley is a very nice framework (may be too small), and I like to play with it :)
Although, it's not ideal. I propose a change to Signal, so it will correctly handle cases of modification of listeners list while dispatching is being in progress.
There are 2 commits:

1. First adds a test case, which fails on current Signal implementation. Signal should notify every listener during dispatch, but if listener is removed when notified (which can happen very often), the next listener is skipped.
2. Second fixes failed test case :) Solution uses SnapshotArray, which freezes array during dispatch. I looked at it's source and it seems it gives very little overhead.

What do you think?

[dsaltares]

Can you please revert this lines?

[dsaltares]

Thanks! Other than the small comment, it looks great. Much appreciated. Can you please commit the fixes and rebase to have a clean history?

[vlaaad]

Here it is, I fixed comments and made it a single commit.

[vlaaad]

Oh.. Looks like I introduced another stupid changes ><
Do you have some kind of eclipse formatter (like libgdx does), so I can use it to keep project's code style and formatting?

[dsaltares]

It's alright, you removed some extra spaces anyway! Thanks :-).