TravisCI: IE8 and AS3

[andyli]

• Enabled testing IE8 (IE8 Unit Tests #2575)
• Took as3 out of allow_failures (As3 disabled Int64 unit test #2665).

[ncannasse]

BTW I just made you a member of the Haxe team so you can now directly push things to the repo ;)

[andyli]

Thanks a lot! That's super cool :)

[ncannasse]

You deserve it, Travis really helps us, although it gives a bit of additional stress to @Simn :)

[Simn]

Hehe, I dread these emails, but it's the good kind of stress. Travis makes writing unit tests a lot more fun because now I know they are actually run. Thanks a lot for your work on this!