Make ghc-ios act more like ghc command

While debugging some things, I found I needed to pass arguments to the ghc processes, like -Wall and -v3. This patch lets ghc-ios pass those arguments on to the child processes.

It also changes the command to process the final argument as the file name WITH the extension. So you run it on fileName.hs instead of fileName. This is more in line with that I expected when I first used the tool. If you would rather not have this behavior I can split this PR into multiple parts.

I also made some documentation changes after running into a couple problems getting going the first time.