[Audacity-devel] More robust project opening

[Dominic M. <do...@mi...>]

Opening projects is now a little more robust.  There's now an
XML close tag handler, which gives the Sequence a chance to
verify itself and make sure that all of the blockfiles were
correctly loaded and are self-consistent.  If not, it replaces
bad blockfiles with a new "silent" blockfile and sets an error
flag.  The Project displays a single error message if any
errors were encountered.  The goal is to let the user know if
there was an error, but to try to degrade gracefully: if only
one track was bad, the others should still open.

SilentBlockFile is now also used by "Insert Silence".

Someone will need to add SilentBlockFile.cpp to the Windows
project file.

- Domini