install: For Ubuntu 18.04+, recommend llvm-10 + clang-10
install: For Ubuntu 18.04+, recommend llvm-10 + clang-10

Currently, `llvm` and `clang` point to LLVM/Clang 6 :(

* Adds `llvm-dev` and fixes spelling for `libclang-dev`
* Adds example for CMake configuration on Ubuntu
RosettaCommons/binder,RosettaCommons/binder,RosettaCommons/binder