Improvements on error handling and JavaScript custom updates; bugfix

...ats/ia2/tapschemamanager/businesslayer/EntityWrapper.java

.../inaf/oats/ia2/tapschemamanager/businesslayer/Schema.java

...t/inaf/oats/ia2/tapschemamanager/businesslayer/Table.java

...af/oats/ia2/tapschemamanager/businesslayer/TapSchema.java

...naf/oats/ia2/tapschemamanager/webapp/CredentialsBean.java

.../tapschemamanager/webapp/CustomPartialResponseWriter.java

...naf/oats/ia2/tapschemamanager/webapp/JSUpdateHandler.java

...ats/ia2/tapschemamanager/webapp/TapSchemaEditingBean.java

TapSchemaManager/src/main/webapp/WEB-INF/web.xml

TapSchemaManager/src/main/webapp/expired.xhtml

...emaManager/src/main/webapp/resources/js/edit-tapschema.js

TapSchemaManager/src/main/webapp/tapSchemaEditing.xhtml

TapSchemaManagerDL/pom.xml

...naf/oats/ia2/tapschemamanager/datalayer/ColumnEntity.java

.../inaf/oats/ia2/tapschemamanager/datalayer/ColumnInfo.java

...inaf/oats/ia2/tapschemamanager/datalayer/Credentials.java

.../oats/ia2/tapschemamanager/datalayer/KeyColumnEntity.java

...t/inaf/oats/ia2/tapschemamanager/datalayer/KeyEntity.java

...naf/oats/ia2/tapschemamanager/datalayer/SchemaEntity.java

...inaf/oats/ia2/tapschemamanager/datalayer/TableEntity.java