(feature request) Include a flag for determining what scripts to include

[zph]

Use case:

• When including data files or non executables in the project
• I want them to not show up in the auto-completion nor in the bulk help text

Feature:

• A flag (and env var value) to exclude files that are not executable per filesystem permissions
• This flag would be passed during function instantiation in tome's shell init configuration

ie:

# Default and current behavior
eval "$(tome init my-commands --include=all ~/my-scripts bash)"

# New extension
eval "$(tome init my-commands --include=executables ~/my-scripts bash)"

@toumorokoshi Is this something you'd accept as a patch under the design conditions of "does not break default backwards compatibility"?