Handle PLIST <date> and <data> elements appropriately

[facelessuser]

Suggestion from https://github.com/wbond/package_control_channel/pull/2660#issuecomment-32909367

Handle PLIST and elements conversions appropriately both from plist and to plist. Must provide a way to convert back to and as well.

See:

• plistlib._dateToString
• plistlib._dateParser
• plistlib._dateFromString

For JSON, there is no easy way to identify plist base64 with 100% certainty. So require base64 to have some unique identifier. Like a dict with a single key, value pair where the key denotes binary data, and the value is the binary data.

{
    "python/object:plistlib.Data": "U29tZSBkYXRh"
}

[facelessuser]

ST3 working on bench. Date converts with no issues between JSON, PLIST, and YAML. Data converts between all three carrying plist data info:

        <data>U29tZSBkYXRh</data>

                {
                    "python/object:plistlib.Data": "U29tZSBkYXRh"
                }

        - !!python/object:plistlib.Data
            data: !!binary |
                U29tZSBkYXRh

ST2 support not implemented yet.

[facelessuser]

ST2 support now in as well.

[facelessuser]

New fixes and cleanup have been applied. This should now work 100%.

Now binary data will just be converted directly to and from this form in YAML:

           -  !!binary |
                U29tZSBkYXRh

Json still converts with the python object since there is no standardized way of storing and recognizing binary data in json.

                {
                    "python/object:plistlib.Data": "U29tZSBkYXRh"
                }