Add initial buffer header
Move buffer functions the the c file
Add buffer init function body
Add buffer flush function
Add buffer function for appending char
Add buffer function for appending string
Add buffer function for appending long
Remove inline declaration for buffer functions
Add accessor macros for buffer string
Add new declarations for alloc and block getter
Implement php_json_buffer_get_block
Replace smart_str with php_json_buffer (not tested)
Finish buffer before encoding return
Decrease length when adding string to json_buffer
Add mark buffer API (empty)
Add buffer marking implementation
Fix buffer realloc size
Fix incorrect buffer length handling
Use buffer block for encoding double values