Set runtime.currentDirectory/libraryPaths in faked webodf.js for out-of-source runs

Frees "production" code from adjustments for out-of-source developer code
Fix broken automatic loading of manifest.json at script location when executing runtime

* Fix extracting the path from a script passed as arg to runtime
* Allow failing on trying to load a manifest file from the current directory
Remove duplicated runtime.libraryPaths setting in docnosis/index.html
Merge pull request #399 from kossebau/cleanupRuntimeLibraryPaths

Fix broken automatic loading of manifest.json at script location when executing runtime & cleanup