Overrode GetHash and Equals in ApkManifestRecord

1. Overrode methods GetHashCode() and Equals() in ApkManifestRecord
class.
Added methods to Patcher to mark files in APKs

1. Added methods MarkFilesDELETE, MarkFilesNEW, MarkFilesUPDATED into
Patcher class. These methods mark files in APKs.