Documentation.

calculate_num_jobs now returns at least 1 job.

 - xref.txt - contains xrefs that were mapped to e! objects during the mapping run
 - external_db.txt - contains the unique list of xref sources from the xrefs above in a format suitable for loading into the existing external_db table

Doesn't do dependent xrefs yet.

Disabled automatic loading of object_xrefs etc, now written to file.

Now assigns an analysis ID or creates one if necessary.

Improved process communication. Implemented parsing.

Temporary utility to dump xref sequences to a FASTA file. Needed for development/debugging of xref mapping system.

Temporary utility to dump Ensembl transcript sequences to a FASTA file. Needed for development/debugging of xref mapping system.

Added storing of dependent xref label and linkage annotation (mainly for GO dependent xrefs so far).