#5 hashes in the cache

[Anonymous]

maybe also the hash of a file (could be MD5) could also be saved in the cache. So only changed files and not all newer file would be send. For example I use webgen and another automatic tool, that both rebuild everything from the sources and so weex always uploads.

Changes:
- when uploading save MD5 hashes in cache file
- if newer file exists and no saved cache exists then upload
- if newer file exists and saved cache exists then do nothing or maybe update file date in cache
- fallback to not using hashes with command line option