readme update for "different languages"

[artofit]

Propose, clearer (at least to me) explanation.

different languages To display months or days in another language than English: Edit ezTime.h file in the library directory and set the EZTIME_LANGUAGE to the desired language, for instance FR or NL or DE, etc. Available languages files are in the src/lang directory, the files there will show you what languages are currently supported. If you add a file in this directory you will add a language, it is that easy. Please submit the files you make via a pull request so others can use ezTime in their own language too.