sea: fix parameter name mapping

- rel_path = ['tm', '.', 'set'] should mean:

'tm': tm parameters first, with /<obj?/tm as main value
'.': then all parameters directly at top level, except 'set'
'set': all parameters  below 'set'
driving happens at object level

- better name mangling (the 1st appearance of the same shortname
  is kept short)

cfg/main/ill1_cfg.py

@@ -14,7 +14,7 @@ Mod('tt',
     io='sea_main',
     meaning=['temperature_regulation', 20],
     sea_object='tt',
-    rel_paths=['tm', 'set', 'dblctrl'],
+    rel_paths=['tm', '.', 'set', 'dblctrl'],
 )
 
 Mod('cc',