pre-build libraries for Julia packages and create default git config

Build and install native dependencies of bundled Julia packages in base image. Reduces build time and space requirement for Julia packages (Dockerfile v13).

Also generating a default git config for users on first login. 

How much testing did you do? Unless we're using Julia with 32-bit-int BLAS here, this will likely hit https://github.com/JuliaOpt/Ipopt.jl/issues/1#issuecomment-37556837 / https://github.com/JuliaLang/julia/issues/4923. Distribution packages for Ipopt are built against shared-library BLAS which will have name shadowing with Julia's ABI-incompatible BLAS when both are `dlopen`ed by the same process.