1.9.13 - Changed Masterkey Backup Strategy

Changes:

• Reworking the masterkey backup strategy: If backup cannot be written to storage, make a bitwise comparsion of masterkey and backup. On read/write error of backup, just only log it (instead of throwing exception) (#90)
• Enhanced fs stats api by total amount written/read of bytes and files (#91)

Fixed:

• possible vulnerability for upstream dependecy guava library (https://snyk.io/vuln/SNYK-JAVA-COMGOOGLEGUAVA-1015415)
  See also the Milestone