Improved first-run experience

Changes since v0.9.0:

• config: Add postSetupOption for SetupOptions that should run after all others (ie. WithValuesFrom* methods).
• config: Add WithValuesFromFlagSet and support for mapping flags to config options and sections.
• config: Add WithValuesFromMap and support for populating a config with data from an arbitrary map.
• config: Add Self method to config.Config interface.
• config: Rename (unexport) config.Configurable to config.configurable.
• cli: Add PluginOptions and LogLevel to cli.Config struct.
• cli: LogLevel can be set from the TOML config file.
• plugin: Rename InitHandler interface to PluginInitHandler to make obvious the difference between it and ShutdownHandler
  • PluginInitHandlers are called whenever a single plugin is initialized while ShutdownHandlers are called all at once and only once when the application is shutting down.
• cmd/squircy: Add command line flags for all options available in built-in irc and vm plugins.
  • Flags follow the convention of -<plugin>-<option> with all underscores _ replaced with dashes -.
  • For example, configure the irc plugin:

    squircy -irc-nick johndoe -irc-username notrealjohn -irc-network weber.freenode.org:6697
    

• cmd/squircy: Add command line flag -plugin-option for configuring extra plugins from the command line.
  • For example, to change the enable_exec option of the node_compat plugin, pass:

    squircy -plugin-option node-compat-enable-exec=true
    

    Or set enabled for the babel plugin:

    squircy -plugin-option babel-enabled=false
    

• cmd/squircy: Fix root directory creation so the directory is created with the proper FileMode.
• cmd/squircy: Add automatic creation of default starting files in root directory, if they do not exist.
  • Static files are embedded using packr2.
• cmd/squircy: Add minimal config.toml and package.json to embedded static files.
• node_compat: Add check to ensure babel is loaded and enabled before node_compat will function.
• vm, script, squircy2_compat: Inherit RootDir option and prefix relative paths in plugin configs with RootDir.
• various: added godocs, improved logging output consistency
• updated README!

Pre-release

This is the first tagged release of squircy3 mostly just as a line in the sand. The codebase has been pretty stable with no major changes and this marks the first step toward a v1.0.0 release.