Support MSVC compiler options starting with "/" #61
Description
There already is a TODO in msvc.rs mentioning this, but I think it is good to have an issue open for better visibility.
It seems quite straight-forward to add support for options starting with / as well.
See: https://msdn.microsoft.com/en-us/library/610ecb4h.aspx
Options are specified by either a forward slash (/) or a dash (–).
Additionally, it might be good to also support options that accept arguments after a space.
If an option takes an argument, the option's description documents whether a space is allowed between the option and the arguments
For example, I have encountered defines being set like /D WIN32 instead of /DWIN32. Maybe this should have a separate issue.