static arrays in various classes need to be able to call ts()

--CRM/Core/Block.php contains two static arrays, $_properties and $shortCuts. Both arrays contain strings that need to be translatable by the ts() function calls.-- (fixed in r1438 + r1439)

--CRM/Core/SelectValues.php contains 14 such static arrays.-- (fixed in r1426)

--CRM/Contact/Form/Search.php contains the $_validContext array.-- (fixed in r1422)

--CRM/Contact/Task.php contains the $tasks and $optionalTasks arrays.-- (fixed in r1421)

--CRM/Core/BAO/CustomField.php contains the $_dataType array.-- (fixed in r1419)