jenkins development: use make -j4 to use all available cores for build

git-svn-id: svn://dev.exiv2.org/svn@3335 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3
jenkins development: retry.  Don't know why cygwin failed last time

git-svn-id: svn://dev.exiv2.org/svn@3336 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3
jenkins development: fix cygwin

git-svn-id: svn://dev.exiv2.org/svn@3337 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3
jenkins development; report build start/finish date/time

git-svn-id: svn://dev.exiv2.org/svn@3338 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3
provide build start/finish time

git-svn-id: svn://dev.exiv2.org/svn@3339 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3