bug(htmlbeautifier): Global installed BeaufitulSoup

### 1. Summary

**If**:

1. I globally install BeautifulSoup,
1. [**path to `site-packages` folder**](https://kristinita.ru/Programs/KristinitaLuckyLink#environment-variable) add to my local Sublime Text environment,
1. `"formatter_version": "bs4"` in my `"codeformatter_html_options"`.

I can't format any HTML file. I get an error in Sublime Text console:

```python
command: code_formatter
error: CodeFormatter

Format error:
prettify() got an unexpected keyword argument 'indent_size'
```

### 2. Environment

+ Windows 10 Enterprise LTSB 64-bit EN,
+ Python 3.6.4,
+ Sublime Text Build 3143,
+ BeautifulSoup4 4.6.0,
+ CodeFormatter 4.1.0.

### 3. Steps to reproduce

I reproduce the problem in a version of Sublime Text without plugins and user settings.

#### 3.1. Without global site-packages path

I install CodeFormatter → I restart Sublime Text → I print in Sublime Text console:

```python
>>> import sys; sys.path
['D:\\Sublime Text Build 3143 x64 For Debug', 'D:\\Sublime Text Build 3143 x64 For Debug\\python3.3.zip', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Lib\\python3.3', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages', 'D:\\SUB044~1\\Data\\Packages\\pyyaml\\st3', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages\\CodeFormatter\\codeformatter\\lib', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages\\CodeFormatter\\codeformatter\\lib\\htmlbeautifier']
```

#### 3.2. With global site-packages path

See [**manual**](https://stackoverflow.com/a/48321114/5951529), how use global Python packages in Sublime Text environment.

For example, my package [**KristinitaLuckyLink**](http://kristinita.ru/Programs/KristinitaLuckyLink) contains lines:

```python
site_packages = (os.environ['PYTHONPACKAGES'])
if site_packages not in sys.path:
sys.path.append(site_packages)
```

These lines add `'C:\\Python36\\Lib\\site-packages'` path to Sublime Text environment in Sublime Text start.

`Package Control: Add Repository` → I paste `https://github.com/Kristinita/KristinitaLuckyLink` → Enter → `Package Control: Install Package` → I select `KristinitaLuckyLink` → I restart Sublime Text → I print in Sublime Text console:

```python
>>> import sys; sys.path
['D:\\Sublime Text Build 3143 x64 For Debug', 'D:\\Sublime Text Build 3143 x64 For Debug\\python3.3.zip', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Lib\\python3.3', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages', 'D:\\SUB044~1\\Data\\Packages\\pyyaml\\st3', 'C:\\Python36\\Lib\\site-packages', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages\\CodeFormatter\\codeformatter\\lib', 'D:\\Sublime Text Build 3143 x64 For Debug\\Data\\Packages\\CodeFormatter\\codeformatter\\lib\\htmlbeautifier']
```

Pay attention to `'C:\\Python36\\Lib\\site-packages'`.

---

Then I open any valid HTML file → Ctrl+Shift+P (⌘⇧p for Mac) → `CodeFormatter`.

### 4. Expected behavior

**If no** `'C:\\Python36\\Lib\\site-packages'`

**or**

`"formatter_version": "regexp",` in `User/CodeFormatter.sublime-settings`:

    HTML file successful beautify.

### 5. Actual behavior

**Else** `'C:\\Python36\\Lib\\site-packages'`

**and**

`"formatter_version": "bs4",` in `User/CodeFormatter.sublime-settings`:

I get an error:

```python
command: code_formatter
error: CodeFormatter

Format error:
prettify() got an unexpected keyword argument 'indent_size'
```

Thanks.