File loading and saving like in gedit
@swilmet
Submitted by Sébastien Wilmet Link to original bug (#735931)
Description
For the file loading, improve the character encoding auto-detection, and be able to manually choose the encoding.
When saving a file, be able to choose manually the encoding and the line ending type.
GtkSourceView has a new API for the file loading and saving, but the front-end code in gedit is not yet reusable. So the gedit code should be made reusable first, and then use it in latexila.