use ph-schematron ant task

[bwbohl]

This is an alternative Ant task that also uses SchXslt works locally on my machine, havent’t tested Windows or Docker environemtn.

[musicEnfanthen]

validate-source:
[schematron] Successfully parsed Schematron file 'D:\Repositories\MusicEncoding\fork_music-encoding\source\validation\mei-source.sch'
[schematron] Validating XML file 'D:\Repositories\MusicEncoding\fork_music-encoding\build\mei-source_canonicalized_v5.1-dev.xml' against Schematron rules from 'mei-source.sch' expecting success
[schematron] JAXP: using thread context class loader (java.net.URLClassLoader@77459877) for search   
[schematron] JAXP: Looking up system property 'javax.xml.validation.SchemaFactory:http://www.w3.org/2001/XMLSchema'
[schematron] JAXP: The property is undefined.
[schematron] JAXP: attempting to use the platform default XML Schema validator
[schematron] JAXP: factory 'com.sun.org.apache.xerces.internal.jaxp.validation.XMLSchemaFactory' was found for http://www.w3.org/2001/XMLSchema

[schematron] XML file 'D:\Repositories\MusicEncoding\fork_music-encoding\build\mei-source_canonicalized_v5.1-dev.xml' was validated against Schematron 'D:\Repositories\MusicEncoding\fork_music-encoding\source\validation\mei-source.sch' and matches the rules

Yay!

[musicEnfanthen]

Thanks for investigating!