Escape newlines in graphviz output (#7)

* Escape newlines when outputting labels

* Close br tag

* Align text to the left when separated by br

* Fix quotes

src/graphviz.rs

@@ -149,7 +149,7 @@ const INITIAL_COLOR: usize = 2;
 /// Returns an html label for the node with the function name and ports for each argumetn
 fn html_label(label: &str, n_args: usize) -> String {
     format!(
-        "<<TABLE BGCOLOR=\"white\" CELLBORDER=\"0\" CELLSPACING=\"0\" CELLPADDING=\"0\" style=\"rounded\"><tr><td CELLPADDING=\"4\" WIDTH=\"30\" HEIGHT=\"30\"{}>{}</td></tr>{}</TABLE>>",
+        "<<TABLE BGCOLOR=\"white\" CELLBORDER=\"0\" CELLSPACING=\"0\" CELLPADDING=\"0\" style=\"rounded\"><tr><td BALIGN=\"left\" CELLPADDING=\"4\" WIDTH=\"30\" HEIGHT=\"30\"{}>{}</td></tr>{}</TABLE>>",
         (if n_args  == 0 {"".to_string()} else {format!(" colspan=\"{}\"", n_args)}),
         Escape(label),
         (if n_args == 0 {
@@ -172,6 +172,7 @@ fn quote(s: &str) -> String {
 }
 
 // Copied from https://doc.rust-lang.org/stable/nightly-rustc/src/rustdoc/html/escape.rs.html#10
+// but added conversion of \n to <br/>
 
 /// Wrapper struct which will emit the HTML-escaped version of the contained
 /// string when passed to a format string.
@@ -191,6 +192,7 @@ impl<'a> fmt::Display for Escape<'a> {
                 '&' => "&amp;",
                 '\'' => "&#39;",
                 '"' => "&quot;",
+                '\n' => "<br/>",
                 _ => continue,
             };
             fmt.write_str(&pile_o_bits[last..i])?;