Adding -u option to command line to allow a program to be specified directly without a file

[TimLethbridge]

This allows a complete (presumably small) umple program to be specified on the command line following the -u option.

Use cases:

• Quick testing, as needed for the homebrew formula (so the -u option would be the only option)
• Adding an extra statement or two to a program compiled from files, such as to suppress warnings. This use case will be further used later to suppress or expect warning messages in the user manual tests that are demonstrating warnings'