include/ and src/ use C++ equivalents of C headers and <...> instead of "..." (to not search in the current directory) where applicable.
Removed empty source file "Integer.cc".
Delete duplicate (and incompatible) declaration of iRRAM_initialize().
Added check whether linking to GMP works + made compile checks more robust.
More OpenBSD-friendly: no "make -C", no indirect shell variables, moved "obj" to "build" to avoid trouble w/ OpenBSD make
Made GMP version check more verbose and moved it as a separate function to m4/.
Use variadic templates for iRRAM_exec: removes need for two identical versions in include/core.h
Remove assumptions about unspecified types from STREAMS -> compiles on OS X 10.9.
Merge branch 'next'

* renamed obj/ to build/ to avoid issues with OpenBSD make
* removed empty src/Integer.cc
* avoid running test programs in configure to support cross-compilation
* use variadic templates for iRRAM_exec and switched order of template params to <class RESULT,class... ARGUMENT>
* use std:: types in STREAMS where possible, otherwise infer via decltype(..) [-> C++-library iRRAM is compiled with also has to be used for all programs linking to iRRAM]
* more #include "..." -> #include <...> where applicable
* fixed out-of-tree builds