allowing create remote with custom fetch spec
adding doc for new param and test to check fetch spec is correctly added
splitting funcionality in two methods to avoid ambiguity with NULL
fixing typo
Fix warnings
Merge pull request #1951 from victorgp/create-remote-plus-fetch

Allowing create remotes with custom fetch spec
Propagate auth error codes as GIT_EUSER in winhttp
Introduce git_cred_default for NTLM/SPNEGO auth