Fixes for various issues.

[djpadz]

This is my version of the script. It addresses the following issues:

• The API base URL is not always api.crowdstrike.com; it may be something else like api.us-2.crowdstrike.com.
• Hardcoded paths, like /tmp/FalconSensorMacOS.pkg and the location of falconctl.
• Lack of documentation around where to get the configuration values.
• The script does not fail (exit nonzero) if something goes wrong.
• Use of python2.7 (deprecated) to parse out JSON