Support converting a project in place

[dsplaisted]

Usually when converting a project, you want to have it update the project file instead of creating a new one. This especially matters because the assembly name and other properties are inferred from the project name.

I'd suggest that if the -o parameter isn't specified for the convert command, that it simply writes the output to the input file.

I tried specifying that the output file should be the same as the input file, but that gives me a CommandLine.MissingRequiredOptionError.

[NotMyself]

If doing this, please make a backup of the original file for recovery purposes.

[srivatsn]

@dsplaisted I've made a change to default to the projectfile path if the output path is not specified. @NotMyself - i don't yet make a backup but have found reverting with git sufficient so far.