Fix new lints from pedantic and be more strict about checking them (#30)

.travis.yml

@@ -7,7 +7,7 @@ dart:
 dart_task:
   - test
   - dartfmt
-  - dartanalyzer
+  - dartanalyzer: --fatal-infos --fatal-warnings .
 
 # Only building master means that we don't run two builds for each pull request.
 branches:

example/example.dart

@@ -26,7 +26,7 @@ main(List<String> args) {
   var port = int.parse(results['port'] as String);
   var standalone = results['standalone'] as bool;
 
-  if (results.rest.length > 0) {
+  if (results.rest.isNotEmpty) {
     print('Got unexpected arguments: "${results.rest.join(' ')}".\n\nUsage:\n');
     print(parser.usage);
     exit(1);

example/src/examples/cow_repository.dart

@@ -66,7 +66,7 @@ class CopyAndWriteRepository extends PackageRepository {
         .where((pv) => pv.versionString == version)
         .toList()
         .then((List<PackageVersion> versions) {
-      if (versions.length >= 1) return versions.first;
+      if (versions.isNotEmpty) return versions.first;
       return null;
     });
   }

example/src/examples/file_repository.dart

@@ -49,7 +49,7 @@ class FileRepository extends PackageRepository {
         .where((pv) => pv.versionString == version)
         .toList()
         .then((List<PackageVersion> versions) {
-      if (versions.length >= 1) return versions.first;
+      if (versions.isNotEmpty) return versions.first;
       return null;
     });
   }

example/src/examples/http_proxy_repository.dart

@@ -48,7 +48,7 @@ class HttpProxyRepository extends PackageRepository {
         .where((v) => v.packageName == package && v.versionString == version)
         .toList()
         .then((List<PackageVersion> versions) {
-      if (versions.length >= 1) return versions.first;
+      if (versions.isNotEmpty) return versions.first;
       return null;
     });
   }

lib/shelf_pubserver.dart

@@ -240,7 +240,7 @@ class ShelfPubServer {
     }
 
     var packageVersions = await repository.versions(package).toList();
-    if (packageVersions.length == 0) {
+    if (packageVersions.isEmpty) {
       return new shelf.Response.notFound(null);
     }
 
@@ -416,7 +416,7 @@ class ShelfPubServer {
 
   Future<shelf.Response> _addUploader(String package, String body) async {
     var parts = body.split('=');
-    if (parts.length == 2 && parts[0] == 'email' && parts[1].length > 0) {
+    if (parts.length == 2 && parts[0] == 'email' && parts[1].isNotEmpty) {
       try {
         var user = Uri.decodeQueryComponent(parts[1]);
         await repository.addUploader(package, user);