Fixes overwriting workflows with vistrails
Get open_vistrail() to create the controller

It seems that add_vistrail() doesn't do its job.
Adds from_root=True for no good reason
Makes do_version_switch() to current validate

Previously, no validation would occur if we were changing to the already
selected version. This was an important optimization. However, this
meant that calling perform_action() then change_selected_version(),
neither of them would validate.

This makes change_selected_version() to current pipeline (re)validate if
the current pipeline was invalid (or not yet validated). This means that
changing to the current version is still fast, but errors will be raised
if present.

The behavior that changes is that you will get exceptions when changing
to an invalid pipeline if it was previously selected.
Makes perform_action() validate

Previously, no validation would occur when performing an action. This
meant that the pipeline stayed unvalidated until the next call to
change_selected_version(). However, the latter call wouldn't validate
without from_root=True because it was effectively changing to the
currently selected version.

This makes perform_action() validate the new pipeline, however it still
won't raise exceptions on error by default. The next call to
change_selected_version() will raise that, thanks to the previous
commit.
Merge branch 'master' into 'fix-open-workflow'

Conflicts:
	vistrails/core/application.py
Merge branch 'pipeline-validation' into 'fix-open-workflow'
Revert "Adds from_root=True for no good reason"

This reverts commit 611a366c0e3ef4b09a11b2ade737cedd6fd15ae3.

Conflicts:
	vistrails/core/application.py
initialize_packages optionally reports missing dependencies

This particular type of error might be expected if you are loading
packages non-interactively. They are not application-level errors, they
just indicate that the package cannot be used.
Don't cry about missing deps on first run

This makes VistrailsStartup set a 'first_run' flag, indicating whether
the default configuration was installed and loaded. In this situation,
the applications ask the PackageManager not to report missing
dependencies.
Don't report MissingRequirements on first run

ModuleRegistry#initialize_package() can now raise MissingRequirement.

PackageManager#initialize_packages() reports missing requirements
separately, and silences that if report_missing_dependencies is False.
Fixed 'Create Version' and 'Locate Version' spreadsheet buttons

packages/spreadsheet/spreadsheet_cell.py:
  We should now use locator, not controller, to find the view.

Ticket: 893
Fixed invalid alias when creating version from PE

Bugfix: Alias error when using spreadsheet button "Create Version"
Fixes typo: MissingRequirement should disable pkg

Fixes fdc56463, MissingRequirement should disable the package just like
InitializationFailed does.
Removes a whole lot of dead code
Fixes whitespace madness in vistrails_module.py

Very long lines because of trailing whitespace.
Removes unused create_default_package()
Removes SmartSource
Fixed alias parameters to get_widget_class

Calls to get_widget_class had not been updated to use descriptor:
  gui/mashups/alias_inspector.py
  gui/mashups/mashups_widgets.py
Merge branch 'hide-missing-dependencies' into 'master'

Conflicts:
	vistrails/core/startup.py