Update README.md

Update README.md

Merge branch 'feature/gcc-plural'

merge from master

Merge pull request #2 from andystanton/feature/add-clang

add lldb

change to clang 3.4

add clang 3.5

try clang 3.5

improve Dockerfile formatting

remove 4.3-4.5

add several gcc

Update Dockerfile

Add US locale as default

Update Dockerfile