Implement a command line tool for generating/compiling Path of Exile filter files.

Author the filter in a mostly-normal style, but the compiler's input format additionally supports:

• Variable declarations and references
• Reusable, parameterizable style blocks
• Multiple BaseType or Prophecy lines in one block

See the example for details on the syntax.

Use the following to compile: go run treaster/applications/poe_filter/main.go --input=example.input --output=example.filter

Move the resulting file to your Path of Exile filters directory.