Added color to the new blockCaret setting

Added the new blockCaret setting, which became available since Sublime Text build 3190 (feb 2019).

The blockCaret setting is especially important for those who use some sort of Vim plugin (like NeoVintageous or ActualVim). Without this setting, block carets on the normal mode are displayed with the same color as selected text, which doesn't contrast very well with the background color.

So, for the new block caret color, I picked the same color as line caret, but with some alpha blending for better contrast.

Credits to @marcovirtual

Increase contrast and brighten up a bit dark-gray elements

#555555 -> #909090 and #989898

Fix ignored tmTheme file in package installation

The .tmTheme file is now in the themes folder, and installing it via Package Control now makes it available under the packages/monokaiC namespace