Package-level declarations

Garbage-free numeric-to-text appenders shared by anything that streams large files (point clouds, feature point frames, etc.) directly to a sink instead of building one huge in-memory string first. Writing Int/Long/Float values via these appenders avoids the per-value allocation that Int.toString()/Float.toString()/string concatenation would otherwise create for every single number — which adds up fast when writing tens of thousands of vertices or points.