Conflicts:
	modules/Bio/EnsEMBL/Hive/Worker.pm

Conflicts:
	modules/Bio/EnsEMBL/Hive/Worker.pm

Conflicts:
	modules/Bio/EnsEMBL/Hive/Worker.pm

The problem was when a worker is contaminated and has to die: remainings jobs
of the batch were not released.
We now have an explicit list of all the cause_of_death that could happen through
a batch, and for which we should free the jobs

(resp 64 and 63 characters).
This simple patch prevents db_cmd from creating such databases with an
explicit message as opposite to the default MySQL error message:
"ERROR 1102 (42000) at line 1: Incorrect database name "

Added 'meadow_user' to Worker object+schema which is now routinely recorded. Also renamed 'host' to 'meadow_host' for consistency

The problem was that "0" was not eval-ed

* version/2.2:
  cause_of_death can be undefined here (for local meadows, for instance)

* version/2.1:
  cause_of_death can be undefined here (for local meadows, for instance)

* version/2.2:
  Backported the recent changes from Ensembl's DBConnection

* version/2.1:
  Backported the recent changes from Ensembl's DBConnection

* version/2.0:
  Backported the recent changes from Ensembl's DBConnection

- use placeholders in "do" commands

This is needed for pipeline_wide_parameters as each value is destringified
independently and the JSON writer would otherwise force writing numbers as
strings

"self-burial" had two meanings:
 - should we release the undone jobs ?
 - should we update the last_check_in field in the worker table ?
The former can simply be found by checking whether the worker already has a
role attached to it.
The latter is only set when a worker registers its own death, and is not set
by the GarbageCollector.