Case Insensitive Device Parsing

This PR is based on PR #285, PR #301 and addresses Issue #263.
It introduces a `regex_flag` attribute in the `regexes.yaml` file to allow case insensitive parsing for the respective `regex`.
This affects the device.family "Spider", "Generic Smartphone" and "Generic Feature Phone".
The JS as well as the Python parser where changed to cope with the new flag.