Refactoring: create SourceListProvider on request
Refactoring: extract regex string as parameter
Refactoring: rename classes

SourceListProvider becomes ListProvider, and FileSourceListProvider
becomes PropertiesFilter. After that we can use them not only for source
list filtering.
Refactoring: rename method and extract parameter
Create class CommandBuilder
Create class XTerm
Transform Terminal into abstract class
Terminal implementations use CommandBuilder
Refactoring: each platform knows its default terminal
Terminal string can be taken from config

Fix #6
Remove Terminal implementations
Print debug info when launch terminal
Add info on terminals into default properties file
Add some documentation
Release version 0.9.11