TNL is not supposed to have any external dependencies, so an empty
config file is useless. If some marginal parts of the project (such as
code for image processing) need to depend on some non-standard library,
they should be split into a separate module/project so that the
dependencies can be properly specified.

For now, the macros are specified as compiler parameters. Client
software using the affected headers will have to do the same.

Now that error handling is done via exceptions, the return value is free
for more sensible things.

The method was either returning true or throwing an exception, so it can
simply return void or throw an exception.

The original was simpler/more readable and we require GCC 5.0 now.

This reverts commit d920a278.

Also added missing 'const' to the getMemoryElement method for host.

Implemented Array:containsOnlyValue.
Restored implementation of ArrayOperations::memoryCompare on host.

Implemented a method Array::checkValue which returns true only if there is an element with given value in the array.

- separate data types for input arrays of binary operations
  (necessary for the equality comparison of two arrays of different
  type)
- added separate template parameter for ResultType, which defaults to
  the RealType
  (the goal is to allow sum of bool vectors into int instead of bool)