jackson-dataformats-csv: copy over recent jackson-core changes

[pjfanning]

jackson-dataformats-csv has its own copy of jackson-core NumberInput and TextBuffer classes.

jackson-core changes that could be of use include:

• Allow use of faster floating-point number parsing (Schubfach) with StreamReadFeature.USE_FAST_DOUBLE_PARSER jackson-core#577
• Use Ryu for Float/Double to String conversions jackson-core#514
• Update ParserBase to support floats directly jackson-core#757

[pjfanning]

@cowtowncoder thanks for merging the fast parser/generator support - this issue also includes FasterXML/jackson-core#757 - is that worth pursuing? That remaining issue was the one where some edge case floats are not parsed correctly because they are first parsed as doubles and then cast to float instead of being parsed explicitly as floats (2 conversions when there should just be 1).

[cowtowncoder]

@pjfanning np, thank you for all these cool contributions.

As to remaining edge cases, yes, I think those would be good to address. Or at very least add (failing) tests cases where necessary. Then we could see how easy fixes are.

I also hope to get Jackson 3.0 development back on track. The one blocking thing right now is that I want to fully decide actual Java Package and Maven group ids.
My earlier idea of just doing jackson -> jackson3 replacement is changing a bit; now I am leaning towards using a new domain, most likely tools.jackson (over com.fasterxml).
But once I figure out the choice there, I can finally start moving packages, so that:

1. jackson-annotations remains exactly as-is, as the sole exception. This means 2.x and 3.x will basically remain in-sync and there should be no need for annotation duplication (unlike with 1.x->2.0 transition)
2. jackson-core will move first, get published, and basically almost every other package must be modified (and re-published) by changing imports. That's lots of work and I don't want to do it many times
3. jackson-databind is next, similarly necessitating lots of work.
4. ... and so on for dataformats, datatypes, modules.

Oh yeah, Jackson 3.x really has no relevance to all parser work here. Just something I'll mention as relative near-term focus, possibly competing with 2.14 release. But I also do want to get 2.14.0 out quite soon -- all the must-haves I had are in (basically just the new DataTypeFeature -- although I think I do want to get "databind" issue 3054 implemented too).

[pjfanning]

@cowtowncoder I think this can be marked as resolved now