sublock 0.1.1

Variants of RwLock that support sublocks, opened for reading if the main `RwLock` is opened for reading, opened for writing if the main `RwLock` is opened for writing.
Documentation 
1

git branch gh-pages && git checkout gh-pages && cargo doc && cp -R target/doc ./ && git add doc/ && git commit -am Docpush && git push -f origin gh-pages && git checkout master && git branch -D gh-pages