Merge branch 'releasebranch' into 'master'

Release of 3.0.1 version of GNUKhata gkcore.

See merge request !177

CHANGELOG

+[18-Oct-2016 Release 3.0.1]
+* Now the signature generated is a 2560 bits RSA key.
+
 [04-July-2016 Release 3.0]
 * Unique feature for attaching official documents with vouchers (invoices, bills etc).
 * Running Dr and Cr totals in printed reports like ledger, trial balance, cash flow and project statement.