Fixed ll_is_subset documentation string
Merge pull request #265 from TheNeikos/fix-ll_is_subset_doc

Fixed ll_is_subset documentation string
Added more explanations to How to Build
Update documentation for static remove_element()
Added a note about make doc
Merge pull request #269 from matthiasbeyer/update-error_code_returning

Update the return for returning errno consts
Merge pull request #268 from TheNeikos/add-more_to_readme

[WIP] Added more explanations to Readme
Fix: c/p error in cmake module. Closes #270
Merge pull request #271 from matthiasbeyer/fix-cp_error_in_cmake

Fix c/p error in cmake/module