[V1] First functional version

Use the following implementation:
- Iterate over all the files searching for names started with the old
  prefix
- Replace the names with the old prefix to names with the new prefix
- Iterate through all files changing references of old name to the new
  name
[V2] Add 'multithreading'

- since the runtime seemed to get longer, use bash's multithreading
  to accelerate implementation;
- create background processes, storing their pids in a 'stack'. Then,
  just wait for them to finish

Better project architecture, creating functions for specific tasks
[FixUp] Fix multithreading

Avoid refactoring the same names by creating a control set
[V2] Add support to test project
[CleanUp] Delete commmented code