Changed some levels to new Audio format
Revert "Added new vectorized textures"

This reverts commit b422c5ee84bf19b7badc4d9fd3df39da1612f967.
Removed music-old
Removed mission 101
Revert "Removed mission 101"

This reverts commit 13cf10a4fa559dabb485f9e9607243f3e41622d0.
Replaced reliefs 41 & 47 with ones from original game

Issue colobot/#299
Show warning if po4a is not installed
Moved interface textures
Moved interface effects textures
Reorganized level files
More level changes
More level changes
Updated author.txt and splash screen
Updated generic help files
Removed unused Russian translations files

These are copies of files in "bots" category
Fixed filenames in Polish translations
Prepared all help files for migration into PO4A
Moved all help files to PO4A

fr, de and ru are still marked as fuzzy - they won't be used until somebody checks that they were moved correctly
Don't require help files to be translated 100% before using them
Removed po files for nonexistent scene205

scene205 never existed in colobot, so what are these files doing here??