Fixed an issue with renaming contigs within or outside of the contig
selector while edits are being made.

The contig name is held in two places - the contig name B+Tree
providing name->rec mapping, and the contig_t struct itself.

To avoid clashes when renaming multiple contigs within the contig
editors the B+Tree is not updated until we hit Save. Similarly edits
are now made on the child IO rather than the base I/O. The act of
flushing the child I/O is what performs the B+Tree update.

Also made the Contig List window perform a contig_lock_write call,
forcing any existing editors to prompt for saving.


git-svn-id: https://staden.svn.sourceforge.net/svnroot/staden/staden/trunk@3105 ba6f2710-ca9f-427c-89d3-5bf716dbc8e1