OSX gets bytes capped at 3F

[zambari]

It took me a while to trace this down, but I was getting incorrect results for some of transmitted values on a mac, namely nothing higher than 0x3F would come through (while the results on windows were correct), I found a list of exceptions in serial.cs, Please consider changing (this is from line 228)

        case RuntimePlatform.WindowsEditor:
	case RuntimePlatform.WindowsPlayer:
	case RuntimePlatform.WindowsWebPlayer:

To following, it fixes the issue on OSX

        case RuntimePlatform.WindowsEditor:
	case RuntimePlatform.WindowsPlayer:
	case RuntimePlatform.WindowsWebPlayer:
	case RuntimePlatform.OSXEditor:
	case RuntimePlatform.OSXPlayer:

[prossel]

Thank you @zambari for your feedback. Could you check if v0.4.0 still has the problem ?