arithmetic operators on durations, dates and times failures (at least 46)

[Sorin Marian Nasoi]

There are at least 46 failures in the Arithmetic operators on durations, dates and times functions:

- 14 test cases in "op-subtract-*" test sets
- 8 test cases in "op-add-*"
- 4 test cases in "op-divide-*"
- 20 test cases in "misc-CombinedErrorCodes"

The attached report was generated using:
./zorba -f -q ../../test/fots_driver/cli.xq -e mode:=run-test-sets -e testSetPrefixes:=PREFIX -e verbose:=true -o results_PREFIX.xml --indent --disable-http-resolution
Where PREFIX is one of the following:
- op-subtract-
- op-add-dayTime
- op-add-yearMonth
- op-divide-dayTimeDuration
- op-divide-yearMonthDuration

Here is the list of failing test cases:
"cbcl-minus-002,cbcl-minus-004,cbcl-minus-006,cbcl-minus-008,cbcl-subtract-dayTimeDurations-003"
"cbcl-subtract-dates-001,cbcl-subtract-dates-002"
"cbcl-subtract-dates-001,cbcl-subtract-dates-002"
"cbcl-subtract-dayTimeDuration-from-date-002"
"cbcl-subtract-dayTimeDuration-from-dateTime-002"
"cbcl-subtract-yearMonthDuration-from-date-002"
"cbcl-subtract-yearMonthDuration-from-dateTime-002"
"cbcl-subtract-yearMonthDurations-003"
"cbcl-plus-002,cbcl-plus-004,cbcl-plus-006,cbcl-plus-008"
"cbcl-add-dayTimeDuration-to-date-003"
"cbcl-add-dayTimeDuration-to-dateTime-003"
"cbcl-add-yearMonthDuration-to-date-003"
"cbcl-add-yearMonthDuration-to-dateTime-003"
"cbcl-divide-dayTimeDuration-by-dayTimeDuration-001,cbcl-divide-dayTimeDuration-by-dayTimeDuration-002,cbcl-divide-dayTimeDuration-by-dayTimeDuration-003"
"cbcl-divide-dayTimeDuration-003"
"cbcl-divide-yearMonthDuration-003"
"cbcl-divide-yearMonthDuration-by-yearMonthDuration-001"
"FOAR0001_9", "FOAR0002-5", "FODT0001-10", "FODT0001-11", "FODT0001-12", "FODT0001-3", "FODT0001-4", "FODT0001-5", "FODT0001-6", "FODT0001-7", "FODT0001-8", "FODT0001-9", "FODT0002-1", "FODT0002-2", "FODT0002-3", "FODT0002-4", "FODT0002-6", "FODT0002-7", "FODT0002-8", "FODT0002-9",