Refactor and unify issue handling in CLI commands

TL;DR;
The aim of this JIRA is to start unification of an issue handling in CLI commands.

Details:
Currently there is a discrepancy between returned error codes if an issue occurred during execution. It depends on the fact whether the CLI command is implemented as @CLIMethod or extending hudson.cli.CLICommand class.

@CLIMethod usually returns 1 in the case an issue occurred, similar situation in hudson.cli.CLICommand returns -1 to the shell.

There is an ongoing effort to extract all CLI commands from the Core to CLI (see JENKINS-22969), so the discrepancy should be removed shortly and consistent error code definition should be set-up on one place only - in hudson.cli.CLICommand.

Currently we should use this semantic in CLI:

• 0 means All right
• -1 means An error occurred

Technically anything else than zero means an issue occurred. Later we can use more precisely defined error codes for the different issues if useful.

Update 07-Jan-2016 (WIP):

TODO

• Refactor core commands to use correct exception classes
• Update javadoc for CLICommand#run
• Unify the handling in CLIRegisterer

Proposed a new unified scheme of exception raising, handling, reporting and error code returning:
Update 12-Feb-2016: - Exception -> Throwable