[API] Replace boost tuple and allow building Walberla without Boost

Closes #48

See merge request walberla/walberla!197

Add /.idea to .gitignore

See merge request walberla/walberla!200

It is not actually used anywhere (since the removal of the old pe), is very hard to read, and essentially contains a custom clone of std::tuple.
If it is ever needed, it could easily be re-implemented using std::tuple and variadic templates in significantly less code.

fix missing assert include

See merge request walberla/walberla!199

Remove boost uuid

See merge request walberla/walberla!191

Remove boost::algorithm

See merge request walberla/walberla!196

Remove boost multi_array

See merge request walberla/walberla!195

Remove boost tribool

See merge request walberla/walberla!192

Resolve "no semicolon after WALBERLA_ASSERT in release"

Closes #90

See merge request walberla/walberla!193

Remove boost::dynamic_bitset

See merge request walberla/walberla!194

This is needed to avoid different behaviour
between release and debug builds

Fixing std::optional (std::experimental::optional does not seem to have the exact same interface as std::optional)

Fix errors introduced with replacing boost::type_traits

See merge request walberla/walberla!190

Replace boost::{type_traits, enable_if and mpl} with standard library features...

See merge request walberla/walberla!182

Replace boost::{type_traits, enable_if and mpl} with standard library features where (easily) possible

replace boost::tuple with std::tuple in pe

See merge request walberla/walberla!187

Replace remaining uses of boost::ref and remove comments about boost

See merge request walberla/walberla!188