Numerous updates to the Spring CLI, primarily for better embedded REPL
shell support:
* Refactor the CLI application to help separate concerts between the
main CLI and the embedded shell. Both the CLI and embedded shell now
delegate to a new `CommandRunner` to handle running commands. The
runner can be configured differently depending depending on need.
For example, the embedded shell adds the 'prompt' and 'clear'
commands.
* Most `Command` implementations have been moved to sub-packages so that
they can be co-located with the classes that they use.
* Option commands are now only used in the CLI, the embedded shell
does not user them and details have been removed from the Command
interface.
* The REPL shell has been significantly refactored to:
- Support CTRL-C to cancel the running process. This is supported
when running external commands and most internal commands.
- Fork a new JVM when running commands (primarily for CTRL-C support
but also for potential memory and classpath issues)
- Change the "continue" trigger from `<<` to `\`
- Support command completion of files
- Add ANSI color output
- Provide 'help' support for internal commands (such as 'clear')
- Remove the now redundant `stop` command
Fixes gh-227
- Look for JUnit test symbols, and add JUnit automatically
- Look for Spock test symbols, and add Spock automatically
- Based on what test libraries were used, invoke relevant embedded testers
and accumulate results
- Make it so that multiple testers can be invoked through a single 'test' command
- Print out total results and write out detailed trace errors in results.txt
- Update based on the new artifact resolution mechanism
