Use libarchive for drumkit archive manipulation. Re-enable import. Implement export.
Allow for automatic (via preprocessor directives) fallback to tar command, if libarchive-dev is not available. On non-windows platforms. If on windows and libarchive is not available, present the user with the information that the drumkit was not exported.
Merge pull request #156 from xnakos/libarchive-for-export

Use libarchive for drumkit archive manipulation.