Koch now copies the correct binary when a '-o' or '--out' switch is passed.

Previously, if the '-o' or '--out' argument was passed after the 'boot' command when using koch.exe, koch would still try to copy 'compiler/nim.exe' to 'bin/nim.exe', either failing or copying the wrong binary. This fixes that by scanning the rest of the command line after the 'boot' command for the '-o' or '--out' arguments.

In addition, parseopt2.getOpt now accepts an optional sequence to read from.