Demomgr release v1.11.0

• The custom file manager now can have a sequence of startup parameters so it can at least navigate to the proper directory.
• HLAE was hardcoded to use hl2.exe when starting TF2, which doesn't exist anymore as of the 64bit update. The executable name can now be configured freely, defaults to tf.exe.
• Most files are now being explicitly opened using utf-8, which should lead to less encoding errors.
• Copypasting something like +4 would pass the int validator and then cause horrible errors. Now impossible.
• Using importlib.resources instead of __file__ to access resources.
• Usernames with spaces in them should now cause at least one issue less (theme loading would previously fail).
• Demomgr now has an icon.
  • It was made by a programmer and as such looks fairly poor.