Merge _s commit [4dad296]

* [4dad296] Merge pull request #524 from jacklenox/dev
* [1c42386] _s: Document background color fallback.
* [4f9492a] Merge pull request #512 from slobodan/content-search
* [31ac4d2] Merge pull request #507 from gatespace/update_pot
* [e24e53e] Merge pull request #453 from grappler/translation-strings
bug fix : copy screenshot.png

init時にscreenshot.pngが壊れる問題の修正
Merge pull request #26 from gatespace/fix_screenshot.png

bug fix : copy screenshot.png
Merge pull request #27 from gatespace/_s_4dad296

Merge _s commit [4dad296]