Invalid dat fixes

[ceeac]

PR #30 cleans up some dat files which caused some warnings during pakset compilation.

[Yona-TYT]

PR #30 cleans up some dat files which caused some warnings during pakset compilation.

Merge

[ceeac]

Another cleanup PR: #32 merges dats referencing the same PNG into one (not all of them, I have not touched the overhead catenary dats for example).
The main reason for this is to work towards being able to compile the pakset incrementally in the future.

[Yona-TYT]

Another cleanup PR: #32 merges dats referencing the same PNG into one (not all of them, I have not touched the overhead catenary dats for example).
The main reason for this is to work towards being able to compile the pakset incrementally in the future.

Merge

[prissi]

Some of those fixes are not very consequent. The stations and bus stops were separated into individual files while the trams were merged. Since those stops were from the same author, I think keeping them merged would have been ok too.