[TIMOB-3796] Ignore files listed in tiapp.xml

This is a feature request to be able to add a list of files to be ignored on build time. Let me quote the helpdesk ticket asking for this: There are certain files that exist in my project that I would like to always ignore when building the application. Occasionally I will use winmerge and it will generate a backup file or occasionally temp files remain in my resources folder. Because of this I have to go through and clean the folder of files I don't want included when the application is built. It would be nice if within the tiapp.xml file there could be a section like:

<ignore-files>tmp, bak, zip, txt</ignore-files>

Helpdesk ticket: http://support.appcelerator.com/tickets/CVP-59987-843/homepage