Add builtin proxy settings #123
Description
Problem
Internet connection in China is kind of broken, and VPN software seems can't catch the traffic from Java programs.
Result in the installer almost unusable in China. Several friends of mine have complained that they can't install impact.
Describe the solution you'd like
Add an option to use proxy.
A ways I can get it working in China
Use cfw-tap virtual adapter to route all traffic into VPN software.
Additional context
Console output:
$ java -jar ./ImpactInstaller-0.9.4.jar
...
DOWNLOADING https://github.com/ImpactDevelopment/ImpactReleases/releases/download/4.9.1-1.12.2/Impact-4.9.1-1.12.2.json
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.
...
Trying some hacks to get this to load!
Undoing hacks!
java.lang.NullPointerException
at java.util.Hashtable.put(Unknown Source)
at java.util......
...