Maintenance release v1.1.0 — modernize project tooling

Replace custom Indexer system with standard gemspec, Travis CI with
GitHub Actions, and add Rakefile. Fix missing block parameter in Time
typecast. Switch tests to minitest. Update URLs to HTTPS, clean up
obsolete files and .gitignore.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: trans

.gemspec

@@ -0,0 +1,21 @@
+name: Test
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: ['3.1', '3.2', '3.3', '3.4']
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - run: bundle exec rake test

.github/workflows/test.yml

@@ -1,8 +1,7 @@
-*.lock
 .yardoc
-doc/
-log/
-pkg/
-tmp/
-web/
-
+doc
+log
+pkg
+tmp
+Gemfile.lock
+*.gem