renameFile: Renames a file safely
Description
Renames a file safely by also asserting that it was correctly renamed without
  side effects.Usage
## S3 method for class 'default':
renameFile(pathname, newPathname, overwrite=FALSE, ..., verbose=FALSE)
Arguments
pathname
The pathname of the file to be renamed.
newPathname
The new pathname.
overwrite
If TRUE and there exists a file with new pathname,
    then it is overwritten. Value
- Returns TRUEif the file was successfully renamed.
   If it failed, an exception is thrown.