set_line_coord_interactive: new mode "custom code"

This may be used to define any perl code for parsing coordinates.
Currently preset to detect values preceded with the strings longitude
and latitude.
data update (mainly things in Uckermark)
data update (mainly around Schoeneweide and Gleisdreieck)

wip: data
Route::Heavy: die if creation of temporary file failed
Route::load: get rid of special "Context"

There's no need for the "Context". The only use was calling a
ResetRoute callback, but this could also be done in the caller.
Route.pm: added OO variants for loading and saving
new test script route.t

Currently just testing the new OO variants for loading and saving,
load_as_object and save_object.
BBBikeGPS: new option for preserving a GPS upload history
fragezeichen2org.pl: new option --plan-dir

With this option items may be marked as PLANNED instead of TODO, if
uploaded gps routes touching these items are found.
use new --plan-dir option for fragezeichen-nextcheck.org-exact-dist target
data update (very minor)