add licensing for urkit

src/main/java/com/sparrowwallet/sparrow/ur/Bytewords.java

@@ -10,6 +10,9 @@ import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.zip.CRC32;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class Bytewords {
     public static final String BYTEWORDS = "ableacidalsoapexaquaarchatomauntawayaxisbackbaldbarnbeltbetabiasbluebodybragbrewbulbbuzzcalmcashcatschefcityclawcodecolacookcostcruxcurlcuspcyandarkdatadaysdelidicedietdoordowndrawdropdrumdulldutyeacheasyechoedgeepicevenexamexiteyesfactfairfernfigsfilmfishfizzflapflewfluxfoxyfreefrogfuelfundgalagamegeargemsgiftgirlglowgoodgraygrimgurugushgyrohalfhanghardhawkheathelphighhillholyhopehornhutsicedideaidleinchinkyintoirisironitemjadejazzjoinjoltjowljudojugsjumpjunkjurykeepkenokeptkeyskickkilnkingkitekiwiknoblamblavalazyleaflegsliarlistlimplionlogoloudloveluaulucklungmainmanymathmazememomenumeowmildmintmissmonknailnavyneednewsnextnoonnotenumbobeyoboeomitonyxopenovalowlspaidpartpeckplaypluspoempoolposepuffpumapurrquadquizraceramprealredorichroadrockroofrubyruinrunsrustsafesagascarsetssilkskewslotsoapsolosongstubsurfswantacotasktaxitenttiedtimetinytoiltombtoystriptunatwinuglyundouniturgeuservastveryvetovialvibeviewvisavoidvowswallwandwarmwaspwavewaxywebswhatwhenwhizwolfworkyankyawnyellyogayurtzapszestzinczonezoomzero";
     private static final List<String> bytewordsList;

src/main/java/com/sparrowwallet/sparrow/ur/UR.java

@@ -3,6 +3,9 @@ package com.sparrowwallet.sparrow.ur;
 import java.util.Arrays;
 import java.util.Objects;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class UR {
     private final String type;
     private final byte[] data;

src/main/java/com/sparrowwallet/sparrow/ur/URDecoder.java

@@ -9,6 +9,9 @@ import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class URDecoder {
     private static final Pattern SEQUENCE_COMPONENT_PATTERN = Pattern.compile("(\\d+)-(\\d+)");
 

src/main/java/com/sparrowwallet/sparrow/ur/UREncoder.java

@@ -6,6 +6,9 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.StringJoiner;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class UREncoder {
     private final UR ur;
     private final FountainEncoder fountainEncoder;

src/main/java/com/sparrowwallet/sparrow/ur/fountain/FountainDecoder.java

@@ -10,6 +10,9 @@ import java.util.zip.CRC32;
 
 import static com.sparrowwallet.sparrow.ur.fountain.FountainUtils.chooseFragments;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class FountainDecoder {
     private final Set<Integer> recievedPartIndexes = new TreeSet<>();
     private Set<Integer> lastPartIndexes;

src/main/java/com/sparrowwallet/sparrow/ur/fountain/FountainEncoder.java

@@ -18,6 +18,9 @@ import java.util.zip.CRC32;
 
 import static com.sparrowwallet.sparrow.ur.fountain.FountainUtils.chooseFragments;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class FountainEncoder {
     private final int messageLen;
     private final long checksum;

src/main/java/com/sparrowwallet/sparrow/ur/fountain/FountainUtils.java

@@ -6,6 +6,9 @@ import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+/**
+ * Ported from https://github.com/BlockchainCommons/URKit
+ */
 public class FountainUtils {
     static List<Integer> chooseFragments(long seqNum, int seqLen, long checkSum) {
         // The first `seqLen` parts are the "pure" fragments, not mixed with any