Use arbitrary primary key instead of composite for allele_sequences.
The PK was a composite of seqbin_id, locus, start_pos and end_pos - this
was also a foreign key for the sequence_flags table.  Using a sequence
simplifies the sequence_flags table and future linking of
allele_sequences with allele_designations.
Update various functions to work with new sequence_flags PK.
Update of tag update to work with new PKs.
Fix query allele sequences by flag status to work with new PKs.
Fix tagging to work with new PKs.
Use placeholders in insert statements.
Modify autotagging to work with new PKs.
Use placeholders in tag update code.
Update TagStatus, XMFA and CodonUsage plugins to work with new PKs.
Complete modifications to support new allele_sequences PK.
Merge branch 'develop' into multi_designations
Remove pending_allele_designations table, move to allele_designations.
Use arbitrary primary key on allele_designations and allow multiple
allele_ids to be associated with a locus for an isolate.
Isolate info: Multiple designations when looking up scheme field values.
Multiple values can now be displayed for e.g. ST.
Propagate provisional formatting if a scheme field value relies on
presence of provisional allele designation.
Support for multiple designations/locus in compositive field values.
Show all designations in sequence tooltip.
Show multiple designations in isolate table.
Use ARRAY_AGG of allele_ids in temp isolate/scheme table.
Perform queries against ANY value in the arrays when searching for STs
etc.
Make sure test for temp table only checks tables from current session.
List scheme loci in query rather than calculate within SQL.
This seems to be much quicker.
Pass record count between pages so this is only calculated once.
Index first three locus fields of scheme temp table.
The query planner won't use any more than this anyway so more are
wasted.