Implement Matrix::loadFromProject

Refs #9970
Prepare to remove d_file_version.

It should not be a instance-global variable, but a parameter passed to
the functions that need it. This commit cleans up the openProject and
openProjectFolder methods of ApplicationWindow in preparation for its
removal.

Refs #9970
Remove obsolete dependency logic.

Reminder: MantidPlot forked QtiPlot 0.9.5, so we'll never encounter a
mantid project file older that 0.9.5, so we can drop special handling
for versions old than that.

Refs #9970
Remove d_file_version.

Refs #9970
Refactor Application::openNote.

This is a stop-gap.

Note itself needs to be refactored to use the IProjectSerialisable
interface in the future.

Refs #9970
Refactor ApplicationWindow::openMantidMatrix

Refs #9970
Replace QString(str.c_str()) with QString::fromStdString(str)

Turns out I've been converting std::strings to QStrings the bad way.
There probably isn't much gain to this way, but if I'm refactoring I may
as well be refactoring correctly.

Refs #9970
Remove curFolder param from App..Window::openProjectFolder

It wasn't being used to replace current_folder, and it probably wouldn't
be. Leaving it in would just cause confusion.

Refs #9970
Remove graph template cruft from ApplicationWindow.

This is unmaintainable and nonfunctional in its current form. Once the
refactoring is complete, it ought to be far easier to re-implement
properly. See #8517 for more information on templates.

Refs #9970