Please support excluding directories while collecting files to be processed

[brlin-tw]

Currently, the logic calls glob.sync without specifying the options argument, this will lead to a problem where one needs to exclude certain directories to be included(e.g. node_modules):

node-ssi/lib/SSI.js

Line 27 in 166c716

var files = glob.sync(this.inputDirectory + this.matcher);

Please allow optionally specified options via the class interface.