Changes main package name and fixes files with weird names throwing errors

Fixes conversion of files with a single quote or square brackets in the filename
Moves all files into the net.knarcraft.ffmpegconverter package

src/main/java/net/knarcraft/ffmpegconverter/converter/AudioConverter.java

@@ -0,0 +1,68 @@
+package net.knarcraft.ffmpegconverter.converter;
+
+import net.knarcraft.ffmpegconverter.streams.AudioStream;
+import net.knarcraft.ffmpegconverter.streams.StreamObject;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+public class AudioConverter extends Converter {
+    private String newExt;
+
+    public AudioConverter(String ffprobePath, String ffmpegPath, String newExt) {
+        this.ffprobePath = ffprobePath;
+        this.ffmpegPath = ffmpegPath;
+        this.newExt = newExt;
+    }
+
+    /**
+     * Reads streams from a file, and converts it to an mp4.
+     *
+     * @param folder        The folder of the file to process
+     * @param file          The file to process
+     * @throws IOException  If the BufferedReader fails
+     */
+    private void processFile(File folder, File file, String newExt) throws IOException {
+        List<StreamObject> streams = probeFile(ffprobePath, file);
+        if (streams.size() == 0) {
+            throw new IllegalArgumentException("The file has no streams");
+        }
+        String newPath = stripExtension(file) + "." + newExt;
+        convertProcess(new ProcessBuilder(builderCommand(ffmpegPath, file.getName(), streams, newPath)), folder);
+    }
+
+    /**
+     * Generates a command for a ProcessBuilder.
+     *
+     * @param executable    The executable file for ffmpeg
+     * @param fileName      The input file
+     * @param streams       A list of ffprobe streams
+     * @param outFile       The output file
+     * @return              A list of commands
+     */
+    private String[] builderCommand(String executable, String fileName, List<StreamObject> streams, String outFile) {
+        List<String> command = generalFile(executable, fileName);
+        List<AudioStream> audioStreams = filterStreamsByType(streams, "audio");
+        AudioStream audioStream = null;
+        if (audioStreams.size() > 0) {
+            audioStream = audioStreams.get(0);
+        }
+        if (audioStreams.size() > 0) {
+            command.add("-map");
+            command.add("0:" + audioStream.getAbsoluteIndex());
+        }
+        command.add(outFile);
+        return command.toArray(new String[0]);
+    }
+
+    @Override
+    public String[] getValidFormats() {
+        return AUDIO_FORMATS;
+    }
+
+    @Override
+    public void convert(File file) throws IOException {
+        processFile(file.getParentFile(), file, newExt);
+    }
+}