Change algorithms to take predicate by value

[vinipsmaker]

This change will allow predicates with non-const methods like the following one:

struct P
{
  bool operator()(boost::string_ref /*v*/)
  {
    ++c;
  }
  unsigned c = 0;
}

Also, it's the approach used by std::*'s algorithms.

TODO

• http://boostgsoc14.github.io/boost.http/reference/header_value_all_of.html
• http://boostgsoc14.github.io/boost.http/reference/header_value_any_of.html
• http://boostgsoc14.github.io/boost.http/reference/header_value_none_of.html