Gradle-generated NSIS installer

See #8
Moved all data into a single directory

See #8
Generating data directory

See #8
Deleted deprecated setting

See #8
Correctly escaped identity file in rsync command

See #8
Key's empty passphrase works on Windows too

An empty string as an argument to the execute() function
in Windows doesn't get to the target process - it's ignored
by the system, as if it weren't there. We need to put a
pair of escaped backslashes instead - just on Win.

See #8
License placeholder

See #8
Windows path's escaping for rsync/ssh

Converts file paths for matching cygwin's style
Fixes #23
JRE 7u72 on Windows

Fixes this nasty bug happening when opening New Case window on Windows:
https://bugs.openjdk.java.net/browse/JDK-8051012

See full stack trace on https://gist.github.com/matiasgarciaisaia/b28fba33aa032d939dcb

See #8