Make "near" group optional in regex

Some errors output with a column number. For these, the `near` group should match.

```
1:2 semicolons error unnecessary semicolon found
```

But some won't. For these, the `near` match should be optional.

```
1 sortOrder error prefer alphabetical when sorting properties
```
#
# linter.py
# Linter for SublimeLinter3, a code checking framework for Sublime Text 3
#
# Written by Jack Brewer
# Copyright (c) 2015 Jack Brewer
#
# License: MIT

"""This module exports the Stylint plugin class."""

from SublimeLinter.lint import NodeLinter, util


class Stylint(NodeLinter):

    """Provides an interface to stylint."""

    npm_name = 'stylint'
    syntax = 'stylus'
    cmd = 'stylint @ *'
    executable = 'stylint'
    version_requirement = '>= 1.5.0'
    regex = r'''(?xi)
        # Comments show example output for each line of a Stylint warning
        # /path/to/file/example.styl
        ^.*$\s*
        # 177:24 colors warning hexidecimal color should be a variable
        ^(?P<line>\d+):?(?P<near>\d+)?\s*\w+\s*((?P<warning>warning)|(?P<error>error))\s*(?P<message>.+)$\s*
    '''
    multiline = True
    error_stream = util.STREAM_STDOUT
    tempfile_suffix = 'styl'
    config_file = ('--config', '.stylintrc', '~')

#
# linter.py
# Linter for SublimeLinter3, a code checking framework for Sublime Text 3
#
# Written by Jack Brewer
# Copyright (c) 2015 Jack Brewer
#
# License: MIT

"""This module exports the Stylint plugin class."""

from SublimeLinter.lint import NodeLinter, util


class Stylint(NodeLinter):

    """Provides an interface to stylint."""

    npm_name = 'stylint'
    syntax = 'stylus'
    cmd = 'stylint @ *'
    executable = 'stylint'
    version_requirement = '>= 1.5.0'
    regex = r'''(?xi)
        # Comments show example output for each line of a Stylint warning
        # /path/to/file/example.styl
        ^.*$\s*
        # 177:24 colors warning hexidecimal color should be a variable
        ^(?P<line>\d+):(?P<near>\d+)\s*\w+\s*((?P<warning>warning)|(?P<error>error))\s*(?P<message>.+)$\s*
    '''
    multiline = True
    error_stream = util.STREAM_STDOUT
    tempfile_suffix = 'styl'
    config_file = ('--config', '.stylintrc', '~')
