Update naming convention for SolrMarc jar files, remove old copies

[todolson]

In VuFind 5.0, the SolrMarc jar file is solrmarc_core_3.1.jar. In release 5.1, this is solrmarc_core_3.2.jar.

Under the import directory, there are two versions of the SolrMarc jar file, SolrMarc.jar and Solrmarc.jar. This causes confusion in Mac OS X because the file system is not entirely case-insensitive. And we want to follow the conventions that the main VuFind project is using.

Please remove the old SolrMarc jar files and switch to the current file name conventions. We can use more recent versions of SolrMarc, but we need to keep up with the naming conventions, with the SolrMarc version in the file name.