Added force option to overwrite measurements when created from Numpy array

lasp/lasp_measurement.py

@@ -737,10 +737,12 @@ class Measurement:
             delimiter: Column delimiter
             firstcoltime: If true, the first column is the treated as the
             sample time.
+            force: If True, overwrites existing files with specified `mfn`
+            name.
         """
         if os.path.splitext(mfn)[1] != '.h5':
             mfn += '.h5'
-        if os.path.exists(mfn):
+        if os.path.exists(mfn) and not force:
             raise ValueError(f'File {mfn} already exist.')
         if timestamp is None:
             timestamp = int(time.time())