Fixing random_vector<>() in tests

Previous version gave linker error (undefined rference to rng/rnd).
Cleaning up examples/CMakeLists.txt
Further cleaning of cmake project files
Mentioned slides in README
Added Karsten's talk
Link to paper
Removing unused typedef
Adding test for combining expressions
More fun with expression combination
Store arithmetic types by value inside expressions

This allows to capture expressions inside temporary variables
without problems with dangling references:

   auto expr = pow(x, 2.0);
Added test showing an alternative to kernel generator

The test uses lazy evaluation by capturing intermediate expressions
with help of 'auto' keyword.
Using Runge-Kutta 2nd order in test/generator.cpp

4th order method resulted in a kernel with too many parameters
which lead to segfault on AMD OpenCL.
typo
Indentation in generated OpenCL code
Copy everything inside expressions except for vectors
A temporary fix for combined expression test in vector_arithmetics

Neither element_index(), nor constants are in vector_domain. Hence, default
as_child behavior is used, which results in dangling references.
This commit introduces local variables to reference to.
Revert "A temporary fix for combined expression test in vector_arithmetics"

This reverts commit 9e243394fbfaf32153033749fccfc7e75484f532.
Moving result of element_index() into vector_domain

This solves issues with dangling references in expressions not containing any
vectors.
Optimizing compound assignments of vector expressions

(x += expr) no longer results in (x = x + expr), but is computed directly.
examples cleanup