Fix --ida, broken in IDA >= 7.4
Fix --ida, broken in IDA >= 7.4

Some of the used methods have been renamed in IDA 7.4:
https://www.hex-rays.com/products/ida/support/ida74_idapython_no_bc695_porting_guide.shtml
Use the new methods to be able to run the generated script in IDA >= 7.4.

Python3 is the default in IDA 7.4. Adapt the script to work in Python3
as well.

Closes https://github.com/fireeye/flare-floss/issues/335

fireeye/flare-floss,fireeye/flare-floss