Run crystal tool format --check on Travis CI (#518)

.travis.yml

@@ -6,6 +6,7 @@ crystal:
 script:
   - crystal spec
   - crystal spec --release --no-debug
+  - crystal tool format --check
 
 matrix:
   allow_failures:

src/kemal.cr

@@ -25,7 +25,7 @@ module Kemal
   #
   # If *port* is not given Kemal will use `Kemal::Config#port`
   #
-  # To use custom command line arguments, set args to nil 
+  # To use custom command line arguments, set args to nil
   #
   def self.run(port : Int32? = nil, args = ARGV, &block)
     Kemal::CLI.new args