version 2.0.0

Fixed:
    - NetcraftEnum
    - DNSdumpster
    - CrtSearch

Removed:
    - PassiveDNS (Reason: Connection timeout)
    - ThreatCrowd (Reason: SSL issue)
    - Virustotal (Reason: it requires an API key)

Remained unfixed:
    - BaiduEnum
    - YahooEnum
    - GoogleEnum
    - BingEnum