* fix for #906, 1) windows paths like C:\a\b weren't accepted because backslashes were treated as escape sequences, 2) common paths like C:\Program Files\Foo\Foo.exe weren't accepted because of the space in the path
* Using anothing approach,
a) backslashes are no longer treated as escape characters,
b) string change to remind people to add spaces
* Removing joplin.pot from the patch, it will be updated later.
* Removing unused code.
