Don't force -Xprinttypes.

Fixed #1001677.(cherry picked from commit 151dbbfbcadfb45861034e8bf108e98f2f2e7b11)
Correctly attach the debugger to a running VM.

Fixed #1001639.(cherry picked from commit 5654dd98fb455a00169298c5be5e3d144a8f1a40)
Merge pull request #415 from dragos/release/scala-ide-3.0.x

[backport] two fixes