Editor can now handle multiple files in tabs. * FileEditorInterface (new class): Interface class fpr the file editor. * FileEditorTab (new class): File editor unit for editing a single file. * MainWindow: Adjusted includes and method calls. * FileEditor: Replaced code that allowed editing a file with code that manages tabs and delegates button clicks. * src.pro: Added new files.

gnulib = [git]git://git.sv.gnu.org/gnulib
gui/qterminal = [git]https://code.google.com/p/qterminal/