Info screen / scan screen improvements

Fixes

• Info Screen:
  • do not warn about missing data if driver returns 0 signal value (#44),
  • present retry/drop rate also as percentage (#38),
  • remove outdated WEP encryption key information (#8);
• Scan Screen:
  • revise and improve access to thread data (#42).

Miscellaneous

• build process now sorts input files for reproducible builds
• miscellaneous fixes, such as typos, email information
• code clean-up