tool: Moved --progress-bar to the global config
tool: Moved --libcurl to the global config
tool_operate.c: Fixed compilation error

incompatible types - from 'OperationConfig *' to 'GlobalConfig *'
tool: Moved internal variable isatty to the global config
tool_metalink.h: Fixed compilation warning

warning: declaration of 'struct GlobalConfig' will not be visible
outside of this function