closes #157, add database infrastructure for different CSL styles

CSL is stored in a new "csl" table. only metadata relevant to updates and selection (ID, date updated, and title) is stored in columns.

chrome/chromeFiles/content/scholar/fileInterface.js

@@ -80,7 +80,6 @@ Scholar_File_Interface = new function() {
 			// get translators again, bc now we can check against the file
 			translators = translation.getTranslators();
 			if(translators.length) {
-				// TODO: display a list of available translators
 				translation.setTranslator(translators[0]);
 				// show progress indicator
 				translation.setHandler("itemDone", _importItemDone);