pareg v0.7.0

• Add Pareg::cur_idx and Pareg::next_idx
• Add Pareg::peek and Pareg::get
• Add Pareg::skip and Pareg::skip_all.
• Add Pareg::jump and Pareg::reset.
• Add Error::TooManyArguments.
• Add color_mode and no_color to ArgError and ArgErrCtx.

• Fix Pareg::remaining and Pareg::cur_remaining.