Fix scoped javascript deserialise()
Refactor basic_element constructors slightly.
Disables pointless "move conversion".
Also reformat.
Take note of negative sizes in invalid bson
Add some more error detection to detect_size().
Add (in)validity test for many more bson test files.
Also fix some mistakes in detect_size()
Fix handling of '\u0000' in json_reader
Refactor json_reader slightly.
Factor out escape sequence parsing.
Reimplement the character identity functions using simple arithmetic.
Healthy performance boost, especially non-utf8 parsing
Add type inference for builder & array_builder
Use vector in array_builder implementation for more performance.
Also remove unneeded defaulted constructors