more documentation added

Rev: doc/internal/array/aggregate_array:1.1
Rev: doc/internal/array/array_index:1.2
Rev: doc/internal/array/array_remove:1.1
Rev: doc/internal/array/array_search:1.1
Rev: doc/internal/array/array_set_index:1.1
Rev: doc/internal/array/copy_array:1.1
Rev: doc/internal/array/push_array_items:1.1
Rev: doc/internal/array/resize_array:1.1
Rev: doc/internal/array/slice_array:1.1
Rev: doc/internal/pike/types:1.1
Rev: doc/internal/program/add_function:1.1
Rev: doc/internal/program/add_storage:1.1
Rev: doc/internal/program/end_c_program:1.1
Rev: doc/internal/program/set_exit_callback:1.1
Rev: doc/internal/program/set_init_callback:1.1
Rev: doc/internal/program/start_new_program:1.1