First stab at adding support for Rust.

test/fixtures/hello.rs

@@ -0,0 +1,3 @@
+fn main() { 
+    log "Hello, world!"; 
+}

test/test_blob.rb

@@ -298,6 +298,9 @@ class TestBlob < Test::Unit::TestCase
 
     # https://github.com/dharmatech/agave/blob/master/demos/asteroids.sps
     assert_equal Language['Scheme'], blob("asteroids.sps").language
+
+    # https://github.com/graydon/rust
+    assert_equal Language['Rust'], blob("hello.rs").language
   end
 
   def test_lexer

test/test_mime.rb

@@ -62,6 +62,8 @@ class TestMime < Test::Unit::TestCase
     assert_equal 'text/plain', Mime.mime_for('.hh')
     assert_equal 'text/plain', Mime.mime_for('.hpp')
     assert_equal 'text/plain', Mime.mime_for('.kt')
+    assert_equal 'text/rust', Mime.mime_for('.rs')
+    assert_equal 'text/rust', Mime.mime_for('.rc')
     assert_equal 'video/quicktime', Mime.mime_for('.mov')
   end