add some color schemes
fix font color of color scheme google
add some new color schemes

新增google+，輕盈與現代戰爭
bug-fix: naming error

修正modern warfare預覽圖命名錯誤
add starcraft_ii

新增「星際爭霸Ⅱ」
fix bugs and add new color scheme 'steam'
remake all preview pictures
Merge remote-tracking branch 'patrick/master' into patrick_color_schemes
original preview images for preexisting color schemes.
lower case color scheme names.
reformat 'author:' lines.
remove color scheme 'roc'.
Merge branch 'patrick_color_schemes' into develop