Add MATLAB ScriptFileType
Propagate 'omero.launcher' value to processor.py

For each launcher type, an 'omero.launcher.<TYPE>' configuration
setting is available so that an executable can be passed to the
processor.py service. For 'omero.launcher.python' special handling
of the empty string is available in order to make use of
sys.executable.
Hard-code better mimetypes in script.py

The plugin will eventually need to use a service
to set the value since third-parties can configure
some unknown file-ending / mimetype pair.

See: https://trac.openmicroscopy.org.uk/ome/ticket/11741
Fix 'launcher' configuration logic in processor.py
Update URL in Edit_Descriptions.py example
Add omero.process.* support for MATLABProcessI subclass

omero.processor.ProcessI subclasses can now be chosen as the
implementation to be used for running scripts. The primary
method to implement is "command" which returns the string
to be executed. By default, `[self.interpreter, "./script"]`
Fix scripts. Thanks to @pwalczysko
Replace file.sha1.val by file.hash.val
Refactor for .m ending

At @sbesson's suggestion, MATLABProcessI has
been changed in order to include a ".m" ending,
simplifying the MATLAB calling code.
Merge remote-tracking branch 'origin/develop' into 11607-scripts
Initial flake8 cleanup of processor.py
Add `cd('%s')` at @sbesson's request
Fix omero4 reference in Edit_Descriptions.py
Merge pull request #1811 from joshmoore/11607-scripts

11607 scripts