distinguish read and read\! (#505)

[jw3126]

fix #505

[c42f]

I started reviewing this but thought we can be much more minimal in fixing this. My preferred style for the fix here: #515

To explain #515 —

• it leaves read! alone so that it remains non-allocating (I think what you've got here would be allocating, though I could be wrong with the latest compiler)
• leaves the tests alone, because IMO the very explicit style is easier to debug when there's a test failure.

Bit frustrating that this previously working feature was removed back in the rush to 0.7 and will be good to have it fixed either way!

[jw3126]

I think you are right, lets close this.

[c42f]

read!(io, myarray) does not mutate myarray::MArray

Yikes, I hope not... checking... seems ok to me.