more internal docs added

Rev: doc/internal/.bmmlrc:1.1
Rev: doc/internal/array/allocate_array:1.1
Rev: doc/internal/array/array:1.1
Rev: doc/internal/array/array_index:1.1
Rev: doc/internal/array/free_array:1.1
Rev: doc/internal/mappings/copy_mapping:1.1
Rev: doc/internal/mappings/free_mapping:1.1
Rev: doc/internal/mappings/low_mapping_lookup:1.1
Rev: doc/internal/mappings/m_sizeof:1.1
Rev: doc/internal/mappings/map_delete:1.1
Rev: doc/internal/mappings/mapping:1.1
Rev: doc/internal/mappings/mapping_indices:1.1
Rev: doc/internal/mappings/mapping_insert:1.1
Rev: doc/internal/mappings/mapping_replace:1.1
Rev: doc/internal/mappings/mapping_values:1.1
Rev: doc/internal/mappings/mkmapping:1.1
Rev: doc/internal/pike/error:1.1
Rev: doc/internal/pike/fatal:1.1
Rev: doc/internal/pike/frame:1.1
Rev: doc/internal/pike/type_field:1.1
Rev: doc/internal/program/program:1.1
Rev: doc/internal/strings/free_string:1.2
Rev: doc/internal/strings/make_shared_string:1.2
Rev: doc/internal/strings/pike_string:1.2