Fix parameter types for compareTo().

Also adding a CHANGELOG and analysis_options since it's strong mode
clean now.

R=cbracken@google.com, leafp@google.com

Review URL: https://codereview.chromium.org//1963283002 .
diff --git a/.analysis_options b/.analysis_options
new file mode 100644
index 0000000..a10d4c5
--- /dev/null
+++ b/.analysis_options
@@ -0,0 +1,2 @@
+analyzer:
+  strong-mode: true
diff --git a/.gitignore b/.gitignore
index bda251a..0dceb6e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@
 .pub
 build
 packages
+.packages
 pubspec.lock
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..9ec23ff
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+## 0.10.5
+
+* Fix strong mode warning in overridden `compareTo()` methods.
+
+*No changelog entries for previous versions...*
diff --git a/lib/src/int32.dart b/lib/src/int32.dart
index c5996f8..786f2bb 100644
--- a/lib/src/int32.dart
+++ b/lib/src/int32.dart
@@ -287,7 +287,7 @@
     return false;
   }
 
-  int compareTo(Comparable other) {
+  int compareTo(other) {
     if (other is Int64) {
       return this.toInt64().compareTo(other);
     }
diff --git a/lib/src/int64.dart b/lib/src/int64.dart
index 2ff4822..b7127ee 100644
--- a/lib/src/int64.dart
+++ b/lib/src/int64.dart
@@ -458,7 +458,7 @@
     return false;
   }
 
-  int compareTo(Comparable other) =>_compareTo(other);
+  int compareTo(other) => _compareTo(other);
 
   int _compareTo(other) {
     Int64 o = _promote(other);
diff --git a/lib/src/intx.dart b/lib/src/intx.dart
index b47a35e..6b4a454 100644
--- a/lib/src/intx.dart
+++ b/lib/src/intx.dart
@@ -7,7 +7,7 @@
 /**
  * A fixed-precision integer.
  */
-abstract class IntX implements Comparable {
+abstract class IntX implements Comparable<dynamic> {
 
   /** Addition operator. */
   IntX operator +(other);
@@ -80,7 +80,7 @@
    */
   IntX shiftRightUnsigned(int shiftAmount);
 
-  int compareTo(Comparable other);
+  int compareTo(other);
 
   /**
    * Returns `true` if and only if [other] is an int or IntX equal in
diff --git a/pubspec.yaml b/pubspec.yaml
index 99f990e..96ccfa0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: fixnum
-version: 0.10.4
+version: 0.10.5
 author: Dart Team <misc@dartlang.org>
 description: Library for 32- and 64-bit signed fixed-width integers.
 homepage: https://github.com/dart-lang/fixnum