Update README: s/,/;/ s/every/all/ s/notably //

Three minor changes:
1. Changed a comma between two independent clauses to a semicolon.
2. Changed "every translations" to "all translations", to match the (plural) number used through the rest of the sentence.
3. Removed the word "notably " from "because notably they don't contain", as 
a. it was unnecessary (superfluous, extra), and
b. no other reasons were given, thus the reason given was *the* reason, not just notable as one among the reasons.

Thanks,
annag