Add support / CLI flag for using `https` protocol instead of `git`

[cupakromer]

On some systems the using the git protocol to connect to GiHub causes auth errors. For example, this git clone:

% git clone [email protected]:tpope/vim-pathogen.git    
Cloning into 'vim-pathogen'...
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Oh other systems, some ports may be blocked which also cause the git protocol to fail.

Adding the ability to configure or pass in a flag to toggle between git (which I think should still be default) and https would be great.

[jatindhankhar]

+1