Remove old HttpRequest files

Old code removed because diff is too large
Extend HttpRequest class

Request parameters are now stored in separate lists. Added methods to
work with URL.
Add overload for ParameterList::add
Use stack allocation instead of unique_ptr in HttpRequest

All ParameterLists now stack allocated. Directory "src" added to CPPPATH
to be able to include internal header files.
Move OAuth related stuff to separate OAuthRequest class
Remove OAuthRequest class
Merge pull request #13 from Melzas/extend-httprequest-class

Extend HttpRequest class