1.3.0: New features - Delete files (experimental), FTP session caching

• Delete files from the FTP server when you delete local files, you'll get a confirmation dialog before that. Experimental Please report any issues.
• FTP session caching (~100-150ms speedup, limited to connectionTimeout option).
• Error dialog when missing any required field in the config file.
• New config options: connectionTimeout (600 seconds by default, timeout for FTP connections and session cache) and sessionCacheEnabled (defaults to true, whatever session cache if enabled = reuse old sessions).
• Code improvements.