v2.0.0

• API Breaking Changes: Remove all functions associated with tag index: myhtml_tree_get_tag_index, myhtml_tag_index_*
• Changes for work with threads
• Removed example replacing_node_attributes_low_level.c. Example is not working correctly. Let the future
• Fix for myhtml_string_destroy function. Sometimes the resources are not free.
• Fix problem with serialization in UTF-8 (0xC2 0xA0)
• Added AVL-Tree for utils