FileDisplayer - pgup/pgdown jumped on wrong line

1. pgup - jumped 2 lines below the correct line (incorrect +-1)

2. pgup/pdgown with combination of number should jump to
     (rows - 1) * number

     but was

     rows * number - 1
Merge pull request #77 from rbalent/file-displayer-pgup-pgdown

FileDisplayer - pgup/pgdown jumped on wrong line
Completion fix when file in Java working directory has same name as token

Steps to reproduce:

Example of directory structure:

homedir/file
homedir/dir1/file2

1. Run application from "homedir" directory
2. Change directory to "drectory1"
3. Input "file<TAB>" and "filefile2" is completed

Test case included.
Merge pull request #78 from rbalent/completer-prefix-file-in-working-dir

Completion fix when file in Java working directory has same name as token