Jlibsedml needs to accept common file path syntax, not just URI syntax

[CodeByDrescher]

According to the SED-ML L1V4 standard, the anyURI type isn't strictly a URI, but rather either a URL or a relative path name. Jlibsedml is designed to parse with java's URI object, but since URIs are not supposed to have spaces, this poses a problem when a relative path containing a space is provided.

See: https://run.biosimulations.org/runs/66cf4c4b7af9fcf21df12a82