Round out the XSLT 1.0 stylesheet and output controls:
- xsl:include folds another stylesheet's templates, keys, globals, and output
at the same import precedence; xsl:import folds them one precedence lower,
so the importing stylesheet's rules win conflicts. Both resolve their href
through the injected document loader, never the filesystem.
- xsl:output drives serialization: method (xml or text), indent,
omit-xml-declaration, encoding, version, and standalone, layered over the
caller's emitter options. The text method emits character data only.
- xsl:comment and xsl:processing-instruction produce comment and PI nodes
from their instantiated bodies.
Templates now carry an import precedence that the matcher ranks ahead of
priority and document order.
Closes#64
Reach full XSLT 1.0 key, numbering, and document parity:
- xsl:key declarations are compiled into an index over the source tree;
the key() function looks nodes up by key name and value.
- format-number() renders a number against a picture string (digit places,
decimal point, grouping, percent), Foundation-free.
- xsl:number generates the context node's position rendered as arabic,
alphabetic, or roman numerals.
- document() resolves an external source through an injected loader so the
transform never reaches the filesystem or network by default.
These hang off an XPath function-table injection mechanism: the evaluator
merges an engine-supplied FunctionTable, letting XSLT register current(),
key(), format-number(), and document() per evaluation.
Closes#63
