GUI: added map loading path clicking

new global structure for map/workspace data
example:

workspace_data =

map_filename: 'workspace_map.bmp'
map: [2048x2048 logical]
map_height: 2048
map_width: 2048
sel_points_px: [3x2 double]
sel_points_m: [3x2 double]
room_width: 28.5000
room_height: 28.5000