Main window
Add AbstractImageBoard
Add AbstractImageBoardMetadata
Format and organize imports
Add metadata implementation FourChanMetadata
Add ImageBoardCollection and basic gui

Added ImageBoardCollection and basic gui with combobox and text area.
Rewrite GUI creation
Move top application classes to app package
Basic object graph of fetching stuff from web.
Add some dependency injection.
Add dummy imageboard, update gitignore.

Add dummy imageboard to test changing of imageboards.
Revert "Add dummy imageboard, update gitignore."

This reverts commit 435100252a9d0ab289779c009a3ab0c9db601545.