Bug 1079546 - Postgres Plugin - Postgres.Inventory.ChildHistory - Past N Days Filter Appears To Hang With Empty Value

Use DateFilterItem instead of "Past N days" SpinnerItem
Use Countdownlatch instead of nested GWT async service calls
Handle parse error and null dates

(cherry picked from commit bc8b90d03a6e6533b65879702936c787a35f3063)

Conflicts:
	modules/enterprise/gui/coregui/src/main/resources/org/rhq/coregui/client/Messages_de.properties
	modules/enterprise/gui/coregui/src/main/resources/org/rhq/coregui/client/Messages_ja.properties