Update changelog for 0.7
Update changelog for 0.7

ssarangi/llvmlite,pitrou/llvmlite,pitrou/llvmlite,numba/llvmlite,pitrou/llvmlite,m-labs/llvmlite,m-labs/llvmlite,ssarangi/llvmlite,ssarangi/llvmlite,numba/llvmlite,ssarangi/llvmlite,markdewing/llvmlite,numba/llvmlite,m-labs/llvmlite,pitrou/llvmlite,markdewing/llvmlite,numba/llvmlite,markdewing/llvmlite,markdewing/llvmlite,m-labs/llvmlite