Replaced copyright sign with (C) to avoid encoding issues

On modern systems files are commonly interpreted as UTF-8 by default,
but these copyright signs are using some ISO-8859 encoding. Better just
write (C) to avoid any issues.
Fixed warnings about conversion from string constant to 'char*'
Fixed compile of worldeditor

Still crashes on startup, though.
Merge pull request #1 from bjorn/master

Some fixes