Javascript JSHint/JSLint/jsl availability, fixes #56

Hi,

updated the javascript linter to work with the most used 3 code linters. Since I couldn't find how the default configuration is created, I'll just paste my configuration here, so you see how it can be configured. The rest is up to you.

Oh, this is for ST3, but I think it'll work with ST2 too.

Here's the config:
```
{
    "user": {
        "debug": false,
        "plugins": {
            "AppleScript": {},
            "C": {
                "args": [
                    "-xc",
                    "-fsyntax-only",
                    "-std=c99",
                    "-Werror",
                    "-pedantic"
                ],
                "cmd": [
                    "clang"
                ],
                "include": []
            },
            "CPP": {
                "args": [
                    "-xc++",
                    "-fsyntax-only",
                    "-std=c++11",
                    "-Werror",
                    "-pedantic"
                ],
                "cmd": [
                    "clang++"
                ],
                "include": []
            },
            "CSS": {
                "cmd": [
                    "csslint"
                ]
            },
            "Coffee": {
                "cmd": [
                    "coffee",
                    "--compile",
                    "--stdio"
                ]
            },
            "Eclim": {
                "cmd": [
                    "eclim",
                    "-command",
                    "java_src_update"
                ],
                "disable": true
            },
            "EmbeddedJS": {},
            "Golang": {
                "cmd": [
                    "go",
                    "build",
                    "-gcflags",
                    "-e -N"
                ]
            },
            "HAML": {
                "cmd": [
                    "haml",
                    "-c"
                ]
            },
            "HTML": {
                "cmd": [
                    "tidy",
                    "-q",
                    "-e",
                    "-utf8"
                ]
            },
            "Java": {
                "cmd": [
                    "javac",
                    "-Xlint"
                ],
                "disable": true
            },
            "JavaScript": {
                // // jsl configuration
                // "regex-config": {
                //     "multiline": false,
                //     "regex": "^\\((?P<line>\\d+)\\):\\s+(?P<error>.+)"
                // },
                // "cmd": [
                //     "jsl",
                //     "-stdin"
                // ]

                // // jsLint configuration
                // "regex-config": {
                //     "multiline": true,
                //     "regex": [
                //         "^(\\s*?)#(\\d)\\s(?P<error>.+)$\\W",
                //         "^.*// Line (?P<line>\\d+), Pos (?P<col>\\d+)$"
                //     ]
                // },
                // "cmd": [
                //     "jslint",
                //     "/dev/stdin"
                // ]

                // jsHint configuration
                "regex-config": {
                    "multiline": false,
                    "regex": "^(.*?): line (?P<line>\\d+), col (?P<col>\\d+),\\s(?P<error>.+)$"
                },
                "cmd": [
                    "jshint",
                    "-"
                ]
            },
            "Lua": {
                "cmd": [
                    "luac",
                    "-p"
                ]
            },
            "Nasm": {
                "cmd": [
                    "nasm",
                    "-X",
                    "gnu",
                    "-I.",
                    "-o",
                    "/dev/null"
                ]
            },
            "PHP": {
                "cmd": [
                    "php",
                    "-l",
                    "-n",
                    "-d display_errors=On"
                ]
            },
            "Perl": {
                "cmd": [
                    "perl",
                    "-c"
                ]
            },
            "Puppet": {
                "cmd": [
                    "puppet",
                    "parser",
                    "validate",
                    "--color=false"
                ]
            },
            "Python": {
                "cmd": "pyflakes"
            },
            "Ruby": {
                "cmd": [
                    "ruby",
                    "-wc"
                ]
            },
            "TODO": {},
            "XML": {
                "cmd": [
                    "xmllint",
                    "-noout",
                    "-"
                ]
            }
        }
    }
}
```

This pull request fixes https://github.com/lunixbochs/sublimelint/issues/56.

Cheers,
Laszlo