doc/dev/MergeLayers

   1 Merge down -> check if another TRWLayer below (HOW)
   2 Actual merge operation:
   3 Take one layer, go thru each waypoint/track of another.
   4 Take old name and value pointers, add to new layer, steal from old layer.
   5 Name conflict:
   6
   7  ______________________________________________________
   8 |_____n_a_m_e_____________c_o_n_f_l_i_c_t______________|
   9 |                                                      |
  10 | The track 'x' exists in both the top layer ('l1')    |
  11 | and the bottom layer ('l2'). What do you want to do? |
  12 |                                                      |
  13 | Delete From  :                   top layer ('l1')    |
  14 | Rename to                                            |
  15 | [        ] in:                                       |
  16 | Autorename                                           |
  17 | Delete All                       bottom layer ('l2') |
  18 | Autorename all                                       |
  19 +------------------------------------------------------+
  20
  21 TODO
  22 * check if another TRWLayer below (HOW)
  23 * Better/less confusing UI
  24
  25 UI (name conflict) suggestions would be appreciated!