Merge pull request jean553#266 from jean553/fix_doc_typo

fix typo from merkle tree doc

Merge pull request jean553#260 from jean553/add_merkle_tree_doc

add merkle tree into the README

Merge pull request jean553#214 from jean553/integrate_drop_at_double_…

…linked_list

Integrate drop at double linked list

Merge pull request jean553#212 from jean553/fix_remove_at_the_end_lin…

…ked_list_when_contains_only_one_node

fix the drop at the end of the linked list when it only contains one node

Merge pull request jean553#211 from jean553/edit_changelog_for_1_0_0_01

Edit changelog for 1.0.0-01

Merge pull request jean553#198 from jean553/b_tree_check_items_are_or…

…dered_in_every_children_node

check position of ordered items in btree