Improvement to pymultinest: allow long filenames

Previously, the outdir and label where limited to 77 characters. This bypasses the hard limit by creating a temporary symlink and then transferring data to the target directory.

test/sampler_test.py

@@ -466,7 +466,6 @@ class TestPymultinest(unittest.TestCase):
     def test_default_kwargs(self):
         expected = dict(importance_nested_sampling=False, resume=True,
                         verbose=True, sampling_efficiency='parameter',
-                        outputfiles_basename='outdir/pm_label/',
                         n_live_points=500, n_params=2,
                         n_clustering_params=None, wrapped_params=None,
                         multimodal=True, const_efficiency_mode=False,
@@ -482,7 +481,6 @@ class TestPymultinest(unittest.TestCase):
     def test_translate_kwargs(self):
         expected = dict(importance_nested_sampling=False, resume=True,
                         verbose=True, sampling_efficiency='parameter',
-                        outputfiles_basename='outdir/pm_label/',
                         n_live_points=123, n_params=2,
                         n_clustering_params=None, wrapped_params=None,
                         multimodal=True, const_efficiency_mode=False,