Initialize wx tpl processor

@inner
@param {Object=} opts the processor options
@param {Array=} opts.plugins the view processor plugins
function initTplProcessor(opts) {
    registerProcessor({
        name: 'wxml2swan',
        // using the existed view processor
        processor: 'view',
        extnames: ['wxml'],
        rext: 'swan',
        options: opts || {
            plugins: [
                wxmlPlugin
            ]
        }
    });
}