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
[AESH-248] Added option to load environment variables of the System into Aesh
Merge pull request #74 from danielsoro/AESH-248

[AESH-248] Added option to load environment variables of the System into Aesh
Added setExportUsesSystemEnvironment in SettingsBuilder
Merge pull request #79 from danielsoro/AESH-248

Added setExportUsesSystemEnvironment in SettingsBuilder
[AESH-249]
initial attempt of FileResource
[AESH-249]
added more methods to FileResource, should be fairly complete
added documentation
added a small test
[AESH-249]
added FileResource to Settings
started porting to use FileResource in æsh
[AESH-249]
further integration of FileResource in æsh
[AESH-249]
æsh should work as previously with FileResource swapped with File
[AESH-249]
added getAeshContext() to ConverterInvocation, this should ensure that the
converter works for all FileResource implementations
[AESH-249]
moved PathResolver to org.jboss.aesh.io
[AESH-249]
renamed FileResource methods
Merge pull request #80 from stalep/aesh-249

Aesh 249