Add benchmark for nth_element
Fix bug with count_if() on AMD

This fixes an issue in which the count_if_with_reduce()
function fails to compile because convert_ulong(bool) is
not supported.

See issue #202.
Add test for count_if() with custom function
Merge pull request #206 from kylelutz/fix-count-if

Fix bug with count_if() on AMD
choose qt4 or qt5
Merge pull request #211 from f-koehler/issue204

choose qt4 or qt5
Improve nth_element performance and unit testing
Merge pull request #212 from roshanr95/nth-element

Nth element
test for program::source()
Merge pull request #213 from f-koehler/issue119

test for program::source()
Capture references with BOOST_COMPUTE_CLOSURE()
Support capturing containers with BOOST_COMPUTE_CLOSURE()
added wait_list as argument and event as return for opengl enqueue_* methods
The test_closure does not require any OpenCL 1.2 features

see #218
Merge pull request #225 from f-koehler/issue217

added wait_list as argument and event as return for opengl enqueue_* methods
Merge pull request #227 from ddemidov/issue-218

The test_closure does not require any OpenCL 1.2 features
Merge pull request #224 from kylelutz/capture-containers-with-closure

Capture containers with closure
Add a merge-path based merge algorithm and change merge to use it

Added a merge_path kernel and a merge algorithm based on it.
Also changed merge to use the new algorithm.
Merge pull request #228 from roshanr95/merge

Merge algorithm
MandelbrotWidget can be closed pressing escape now