Remember position and size of window.

[koron]

When restarting shiba after changed window size and position, it was reseted.

I have realize this with Windows 64bit version.

[rhysd]

I implemented restoring last window state at app starting in acffd0e. I tested this on OS X 10.11.4 and Windows 8.1.

This improvement will come with 1.0.1 release 👍