can't catch parse error Maximum call stack size exceeded on safari

[kaqiling]

Hi, I'm using mermaid, but I find a problem in https://github.com/knsv/mermaid/blob/master/src/mermaidAPI.js#L291. When flowchart contains a Chinese symbol like '；' or '《' , Chrome will catch Maximum call stack size exceeded, but Safari will call recursively and comsume memory endlessly, and I can't do anything on Safari.

[kaqiling]

Please paste code like

graph LR
A--》B

in http://knsv.github.io/mermaid/live_editor/ in safari browser.
I use mermaid in Mac OS x WebView, the bug is also produced in my application. And chrome is ok.
If someone input Chinese symbol like '《' by a mistake, we should tell him or her invalid syntax instead of doing noting and let the application unresponsive.

[kaqiling]

also for #405

[tylerlong]

Issue diappeared: https://mermaidjs.github.io/mermaid-live-editor/#/edit/Z3JhcGggTFIKQS0t44CLQg/error/TGV4aWNhbCBlcnJvciBvbiBsaW5lIDIuIFVucmVjb2duaXplZCB0ZXh0LgpncmFwaCBMUkEtLeOAi0IKLS0tLS0tLS0tLS1e