[QA] Remove unneeded include statement.
[QA] Remove unused viewport variables.
[QA] Tidy up preferences.c
Add tooltips for Preferences and Layer Parameters.

Only set a few tips, as most values are self explanatory.
Align all VikLayerParam data usage and use better index referencing.
Change TrackWaypoint properties that are radiogroups into combo boxes for compactness of displayed dialog.
[QA] Add specific enumeration for route finder tool
[QA] Better variable name usage following the change from name to an id.
Optimise: get reference to VikWindow only once per TrackWaypoint layer drawing update.

Also makes the code a little more compact.
[QA] Use specific type GHashTable *, instead of generic gpointer.

Not quite sure why I thought I couldn't use the proper type at the initial time of writing this code!
Probably got carried away as tracks + waypoint types can't be used directly.
[QA] Factor the way to compute window's name
[QA] Mark some GPS layer strings for translation.
Allow attempting to open a URL in a waypoint comment or description.

Very simple check to see if the text starts with 'http' before attempting to open it.
Fix routes display in different coordinate views.

Missed from the GPX-Routes code addition SHA: 0d2b891f5f4673f0dd1142dcd7e1eb08e4248090
Avoid CRITICAL warnings when updating a waypoint. Check the symbol value is something before attempting to use it.

Error introduced in commit SHA: 70cefedcb427c34e2e3db3bbfcc7e140d55b31a8