test: Started adding tests for Cache module
test: added quick Log::Log4perl config from Mayhem
Cache: renamed 'dependencies' to get_dependencies

- Handle when 'filename' argument is undef
- Add check for 'linux-[gate|vdso]'
- Remove checks for sort and return_type, they're optional
app: debug dump dependencies found by script
File: don't die when attrib validation fails

- Simplified attribute validation for 'file' attribute, just returns
  true/false and lets Moo deal with the error message
Cache: fix references to file/filename

- Moved 'get_dependencies' ahead of 'add'
- Changed 'print' statement to 'say'