+ Added checkbox to enable mercator projection
+ Added checkbox to show/hide position dates
+ Extended position dates by rafos day
+ Added colors for trajectories
/ Improved soundvelocity caluclation
+ Added clock error calculation

+ Added soundsources/colorregister package that is used to assign a color
  to a specific sound source.
+ Added an edit field to the upper and lower boundary adjustment section
+ Added a histogram plot of the TOAs
/ The soundsource color legend shows only the color of an applied sound
  source, white otherwise.

Bugfix:
  When soundsource has been applied, the zoom function was not functioning
  anymore.

Toa table:
  It is now possible to select the duplicates in the toa table, and the
  the plot will zoom to it.

With these functions it is possible to check a complicated struct if a
specific member exists.

It is now possible to select TOAs and shift them by a given value.