Remove buffer management calls from tokenizer

[tgockel]

The following functions were deprecated in tokenizer as of version 1.2. They should be removed in 2.0.

• jsonv::tokenizer::buffer_reserve (size_type sz)
• jsonv::tokenizer::min_buffer_size ()
• jsonv::tokenizer::set_min_buffer_size (size_type sz)

[tgockel]

Removed tokenizer in efc80dc.