Delete the parser code.
Add initial parser code.
Fix double quoted scalars reader.
Fix/optimize hexadecimal number parsing.
Correct the parser's code style.
Update program design of the parser.
[parser] Add single quoted scalar reader.
[parser] Little redesign.
[parser] Add flow sequence reader.
[parser] Add block sequence reader.
[parser] Add flow mapping reader.
[parser] Drop the block sequence reader.

It's broken by design and does not work properly.
[parser] Corrent `readLineBreak`.

Make it do exactly "reading a line break" and nothing beside.
[parser] Remove an orphaned `readBlockSequence` call.
[parser] Join the flow collection readers.
[parser] Lint.
[parser] Rewrite `readSeparation`.
[parser] Rewrite `readFlowCollection`.
[parser] Remove unused KIND_* constants.
[parser] Add the plain scalar reader.