Removed redundant `inline` declarations
* all member functions of this library are defined inside the class defintions
** as stated in chapter 9.3 of the ISO C++14 standard member functions that are defined in a class definition are marked as `inline` implicitly
*** i.e. this also includes `static` member functions
*** this means that all `inline` declarations are redundant and can be removed without consequence
* this was done to remove unnecessary cruft in the attempt of further improving readability
* changed example in custom type documentation accordingly
* aligned some of the template parameter declarations visually