Cleanup-idea

[rrrlasse]

There are lots of initial index checks like "if (end == (size_t)-1) end = m_len;" and lots of optional start/end arguments. Find out what functions are exposed to user and delete these checks and optional arguments from all but those functions.

[astigsen]

Lets keep them. While some of them may be superfluous, they have actually caught quite a few errors for me during development.