Fixes debian install issues.
Adds building of extensions for supported platforms. Enables building on different platforms.

Conflicts:
	debian/control
Removes unnecessary bin dir.
Fixes typo in postinst file.
Adds ability to load locally or from the internet.
Adds saving dialog.
Adds share facility.
Adds share and load images.
Allows loading from the command line
Fixes small spacing issue.
Fixes labels on save and share windows.
Ensures that the directory exists when trying to write a file.
Allows spaces in filenames.
Consistently positions the dialog windows.
Adds loading cursor when uploading and downloading from the internet.
Adds title to info window.
Sets the title of the IO dialogs.
Moves creation of the save directory to the base class of all IO dialogs.
Ensures that everything is killed on exit.
Opens Sonic Pi maximised.