ZIP Importer: Bad include file paths in XSLT stylesheet + Unnecessary .swp file

**Include-file paths:** The Zip Importer sub-module contains a DC-to-MODS XSLT stylesheet. However, this file references other stylesheets (via xsl:include) using a relative path -- that ultimately leads nowhere. Since the files cannot be found, the transformation fails and MODS is not successfully created upon import. Errors similar to the following are logged by Drupal: 
> * Warning: XSLTProcessor::importStylesheet(): I/O warning : failed to load external entity "[root_path]/sites/all/modules/islandora_importer/modules/zip_importer/xsl/inc/dcmiType.xsl"
> * Warning: XSLTProcessor::importStylesheet(): compilation error: file [root_path]/sites/all/modules/islandora_importer/modules/zip_importer/xsl/simpleDC2MODS.xsl

In this PR, the include paths are updated to point to loc.gov, allowing the transformation to be successful.

**SWP file:** The directory `islandora_importer/modules/zip_importer/xsl/` also contains an unnecessary .swp file, probably leftover from when the XSLT was being edited.