lossless

- remove named printer classes

- remove redundancy between AObjectPrinterFactory and PrintVisitor

- remove redundant List- and RecordPrinters

- introduce AbstractPrintVisitor

Change-Id: I692c04dd1b3aa8e7adccfe960615f0fc2df6fe26

Reviewed-on: https://asterix-gerrit.ics.uci.edu/882

Reviewed-by: Yingyi Bu <buyingyi@gmail.com>

Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

1. MISSING repsents the value of a non-existing field in a record

or an out-of-bound index access of a collection;

2. NULL represents that the value of an optional field in a record

is unknown or the value of existing collection entry is unknown.

3. Unit tests for all missing/null-in-missing/null-out scalar functions.

Change-Id: Ia49ed8474bfc5d6604231819065117468c5b0897

Reviewed-on: https://asterix-gerrit.ics.uci.edu/846

Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

Reviewed-by: Till Westmann <tillw@apache.org>

Change-Id: Ie0252fef069ee93db6e32e13a13ebb11df5ce913

Reviewed-on: https://asterix-gerrit.ics.uci.edu/877

Reviewed-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

Reviewed-by: Yingyi Bu <buyingyi@gmail.com>