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Use Hikari Connection Pool instead of Postgres default, currently properties hacked around.

Conflicts:
	intermine/objectstore/main/.classpath
	intermine/objectstore/main/src/org/intermine/sql/Database.java
Replace ObjectStoreWriter connection if it has been closed somehow.
Read properties for HikariCP connection pool, alter access to underlying PGConnection.

Conflicts:
	intermine/objectstore/main/.classpath
	intermine/objectstore/main/src/org/intermine/sql/Database.java
Update database connection properties for new connection pool.
Fix casting to PGConnection.
Export postgres jar.

Conflicts:
	intermine/objectstore/main/.classpath
Close the connection pool correctly.

Conflicts:
	intermine/objectstore/main/src/org/intermine/sql/Database.java
Less log output of ids.
Extend timeout when checking connection is still valid to avoid build errors.
use postgres JDBC driver that works with Java 6. We should use maven so each instance can use the best driver
corrects paths
changes the default settings for postgres connection pool