moban v6 api update

[chfw]

reference: moremoban/moban#302

No longer, the first parameter is a list of directories but an instance of fs.multifs.MultFS.

as the following:

class Engine(object):
    def __init__(self, template_fs, options=None):

[chfw]

@PrajwalM2212 , you have also contributed two template plugins. would you like to take this plugin forward to moban v0.6.0+ with pyfilesystem 2 support?