Tweaks to the Maven and OSGi build files

  * the `maven-dist` target now copies over the jar built from the `jar` target
    (isntead of re-packaging from scratch). This notably means the maven
    artifact will contain the OSGi metadata added by the `jar` target.
  * in the OSGi bnd configuration file (used to generate OSGi metadata), only
    the required packages are explicitly listed, all the other package dependencies
    are set as optional. This notably means that all the proprietary libs in
    the classpath of the `compile-everything` target will be declared as optional
    dependencies in the OSGi manifest.
  * in the Maven POM, updated Saxon's version to 9.4.0.7.
  * in the Maven POM, made the Jing and TagSoup dependencies optional
  * in the Maven POM, added an optional dependency for Henri Sivonen's
    html-parser (back in Maven since version 1.4)
  * in the Maven POM, added optional dependencies for javax.mail and
    xmlunit.
Merge pull request #91 from rdeltour/maven

Tweaks to the Maven and OSGi build files
Bump version number to distinguish trunk from last real release
Note the duplicate step type in the message about ... duplicate step types
Fix issue #92, throw an XPathException not an XProcException because Saxon catches the former and not the latter
Cleanup test suite targets; move extension tests to http://xmlcalabash.com/tests/
Attempt to workaround issue #94, make sure output-base-uri is handled correctly
XML Calabash 1.0.10-94 released
Be careful when copying attributes in XInclude; if it came from the xi:include element, don't copy it from the target element too
Fix issue #108 as suggested
Fix issue #107 make sure the prefix associated with an error code is declared
Fix issue #103 variables with no prefix are in no namespace
Fix issue #102 allow sequences on p:try outputs
Fix issue #101 allow the XProcURIResolver to function as a Saxon XQuery ModuleURIResolver
Fix issue #98 upgrade to Apache HttpClient 4.2.5; props to jamesrdf for the patches though I applied them manually and tinkered a bit
Apply fixes outlined in issue #99 lots of extensions to the Ant task and a variety of code cleanups
Bump version properties to distinguish intermediate builds from releases
Ooops
Fix issue #104 by adding source/target versions in the ant build file
Attempt to fix maven targets so that saxon version is reflected in the artifact names