Fragile release 2.6.3.177

[C Burch]

I just uploaded the latest JAR file, including some post-2.6.2
revisions for the Portuguese translations and the following minor
features:

Feature: Saving project files is more cautious, creating a backup
before starting to write to disk and recoving from the backup if for
some reason the save is detected to fail (whether nothing has been
written to the file or an error has occurred while saving).

Feature: Individual subcircuit instances can have a label, in addition
to the "shared label" that is displayed in the center of each instance
of a subcircuit.

Feature: Added an enable input to the multiplexer, demultiplexer, and
decoder, and added the Disabled Output attribute to the priority
encoder.

Feature: During a rectangular selection, the rectangle is drawn with a
light blue, and components that will be affected are indicated with a
slate-blue outline.

Bug fix: When simulation is disabled, selecting Tick Once will still
cause a tick once the simulation is stepped.

-Carl