add deprecation warnings to the log.

src/main/java/com/falsepattern/lib/api/Deprecation.java

@@ -0,0 +1,10 @@
+package com.falsepattern.lib.api;
+
+final class Deprecation {
+    static void warn() {
+        new Exception("\nDEPRECATION WARNING\nDEPRECATION WARNING\n" +
+                      "Someone used the deprecated FalsePatternLib api.\n" +
+                      "This api will be replaced in FalsePatternLib 0.7! You should probably update your mods.\n" +
+                      "See the following stacktrace for hints on what mod could be the cause.").printStackTrace();
+    }
+}