Introduce kind-of coding standards (2 spaces + JSHint rules applied).

Whole code is now way more consistent. No need to define globals for
JSHint.
Provide simple JSDoc documentation.

Needs to be updated with sample usage later on.
Getting rid of not really necessary variable.
Changes for readability purposes.
Rename basic options, provide more easy to understand option names.
Rewrite "sumTo" function a bit. Make sure it won't return NaN (limit >
length).
Rewrite code a bit to make clear definition and assignment blocks.
Let garbage collector collect some variables much faster (as they're no
longer in use).

Define variables in function scope rather than outside of function.
Merge pull request #1 from msblaze/more-consistent-api

More consistent code