Regex syntax match

[mvoidex]

In addition to first pull request I've implemented syntax_match option, which sets syntax if command matches specified regex.

For example:

"syntax_match": {
    "^svn\\b.*\\bdiff\\b": "Diff"
}

Will set Diff for commands like svn diff ..., svn log -l 10 --diff $file

[ci70]

Please implement this in the main brach. Thanks.