Adds converter modules and sorters

Converters are now the result of combining multiple modules, and running them in the selected sequence. I hope to be able to completely remove converters by replacing them with templates that simply run some modules in a sequence, before running FFmpeg. Then I want to be able to parse a command into a template, so users have full control of what a template does.

Sorters each sort a list of streams after a single criteria. They can be chained in order to create complex chained sorters.

src/main/java/net/knarcraft/ffmpegconverter/property/MinimalSubtitlePreference.java

@@ -0,0 +1,38 @@
+package net.knarcraft.ffmpegconverter.property;
+
+/**
+ * A representation for different preferences related to minimal subtitles
+ *
+ * <p>Minimal subtitles are also referred to as partial subtitles or signs and songs. For Japanese media, they are aimed
+ * at users that understand the spoken language, but struggles with reading, or when things are said too fast or in an
+ * odd rhythm (singing). In american movies, some partial subtitles only translate non-english spoken language. Some
+ * dubbed movies have subtitles that only cover signs, text or logos in the original language.</p>
+ */
+public enum MinimalSubtitlePreference {
+
+    /**
+     * Only map minimal subtitles
+     */
+    REQUIRE,
+
+    /**
+     * Prefer minimal subtitles when available
+     */
+    PREFER,
+
+    /**
+     * Don't do any changes in sorting based on minimal subtitles
+     */
+    NO_PREFERENCE,
+
+    /**
+     * Avoid minimal subtitles, unless it's the only available choice
+     */
+    AVOID,
+
+    /**
+     * Don't include minimal subtitles, no matter what
+     */
+    REJECT,
+
+}