add regex for url in message, add word-break to .chat-box

In Squircle.js
---
#### 1. plainTolink()
Function `plainTolink(arg)` make uri in plain-text to hyper-link-text.
for example, when Input was like bottom,
```html
안녕하세요. 저는 이재영(http://lee.jaeyou.ng/) 입니다.
```
After doing plainTolink(Input), you can see Output:
```html
안녕하세요. 저는 이재영(<a href='$1' ~~ class='linkInMessage'>http://lee.jaeyou.ng/</a>) 입니다.
```

#### 2. change `.textContent` to `.innerHTML`
I changed .textContent to .innerHTML in line 434.

origin:
```javascript
messageElement.textContent = plainTolink(message);
```
changed:
```javascript
messageElement.innerHTML = plainTolink(message);
```
Because textContent treat children tags as plain text strings.

In Squircle.css
---
#### 1. add word-break to .chat-box
To wrapped visualization, I used `word-break: break-all;`.

#### 2. add .linkInMessage
yep. no comment.