Console::lineedit can return -1 to indicate input error and -2 to
indicate the program is closing. But most users don't check possible
unusual return values which can lead to exit hang.
* Paint, filter, and brush state is now saved between calls.
* Added 'all' paint option to set material, shape, special, and variant at
the same time.
* Added tiletypes-here (like liquids here, except is uses the saved brush
settings)
* Added tiletypes-here-point (like liquids here, always only the tile under
the cursor)
* Added tiletypes-command: runs tiletypes commands seperated by ';' tokens
(affects saved state)
* Make the internal workings match liquids a bit more
* Give brush objects a descriptor string
* Make Core::cheap_tokenise available