Issue #1542682 by Berdir: Convert exception classes in field.module to PSR-0.

core/modules/field/field.api.php

core/modules/field/field.attach.inc

core/modules/field/field.crud.inc

core/modules/field/field.module

core/modules/field/lib/Drupal/field/FieldException.php

.../field/lib/Drupal/field/FieldUpdateForbiddenException.php

...dules/field/lib/Drupal/field/FieldValidationException.php

.../field/modules/field_sql_storage/field_sql_storage.module

...es/field/modules/field_sql_storage/field_sql_storage.test

core/modules/field/modules/list/list.module

core/modules/field/modules/list/tests/list.test

core/modules/field/modules/text/text.test

core/modules/field/tests/field.test

core/modules/field/tests/field_test.field.inc

core/modules/taxonomy/taxonomy.test