* moved the sprite renaming out of the file system entirely into a caller-provided callback.
* renamed several functions to closer match the terms of a file system.
* moved the VM interface out of the implementation.
This is now being managed by the main file system class. The single lumps should only concern themselves with the actual data they manage, not with how the file system presents them to the outside.
The IWAD detection code was also switched to use a file system wrapper instead of looking at the single files directly.
The main exits are initiated from code that cannot filter this back to D_DoomMain easily so the exception is the only way to get there.
The 3 main points of exit are:
* quit/exit CCMD
* quitting the menu through ST_Endoom
* receiving a quit message on the main window.
This was done for two reasons:
1. It forces loading of zd_extra.pk3 for the stock IWADs, eliminating a certain kind of user error.
2. It removes the stock IWAD definitions for custom games that distribute the engine along with their data, so that it doesn't pick up on Steam and GOG installations and shows an inappropriate IWAD picker.
Unlike the other games this required a bit of patching of the IWAD's data with a new MAPINFO so it needs to be in a separate .pk3 file loaded after the IWAD.
Since this needs to be loaded after the IWAD it was also possible to add a small DECORATE lump which fixes a few errors inherited from the original Dehacked patch, like monster counting bugs and unintentionally shootable decorations.
The episode titles required a workaround because the CQ3 episodes do not contain names in text form: If this is the case, the patch name will be used as a string table identifier to get a matching text for localization.
This is for IWADs that contain content which clashes with the engine and must be removed. The primary reason are the unimplemented characters in Raven's BigFont.
For the Doom IWADs the provided font looks almost identical to the characters used on the title patches. So, for any level name that got replaced in some language, it will now check if the retrieved name comes from the default table, and if not, ignore the title patch and print the name with the specified font.
This also required removing the 'en' label from the default table, because with this present, the text would always be picked from 'en' instead of 'default'. Since 'en' and 'default' had the same contents, in any English locale the 'default' table was never hit, so this won't make any difference for the texts being chosen.
Last but not least, wminfo has been made a local variable in G_DoCompleted. There were two places where this was accessed from outside the summary screen or its setup code, and both were incorrect.
Previously, only .wad files can specified without file extension for -iwad command line option
For example, -iwad square1 will load square1.pk3 as IWAD
