Fix opening file from URI

[joshas]

My attempt to fix #419 . Only tested with FTP provider and local provider. Also tested with file names containing spaces on FTP - no problems with opening them.

[MeanEYE]

Am not sure this will work with all the cases.

[joshas]

I presume there are only two types of paths: local (ones without ://, like /usr/local/bin/) and URI (ftp://, smb://, etc).
What other cases should I try to test? I'll try to set up connections to real protocols and test with them. Any corner cases that I should be aware of, e.g. illegal symbols, spaces in file names?

[MeanEYE]

Unicode characters, symbols, etc. Without encode path I feel it might fail but do test and let me know. I could very well be wrong.