Updating README file

closes #32
typo
Merging Doxygen and GitHub documentation
Mention github repo in README

README also serves as doxygen main page now.
Removing exclusive scan from external/boost_compute.hpp

Merging partial results for exclusive scan is not as straightforward as for
inclusive one. Removing this for now.
Fixed links in documentation, returned to default color scheme
Removed tabs from README
Show vendor in devlist
Workaround for a bug in AMD OpenCL

http://devgurus.amd.com/message/1295503#1295503
Show device extensions in devlist

Thanks to @Quanteek for the idea.
Add a linebreak for readability
Sort extensions in devlist output
Fixing a bug in vex::random::philox
Simplified boost::compute interaction

Introduced
vex::compute::begin(const vex::vector<T>&, unsigned dev) and
vex::compute::end(const vex::vector<T>&, unsigned dev).

The functions return boost::compute::buffer_iterators for use in
boost.compute algorithms. This is possible due to recent changes in
boost.compute.
Revert "Simplified boost::compute interaction"

This reverts commit 0e6527fa943d1270b30fa71b575014b0ce54dc46.

boost::compute::buffer_iterator does not own its buffer after all.
Fixing determination of CPU devices

CL_DEVICE_TYPE is actually a bitset. This fixes issues with pocl.
devlist.hpp needs <random>
Refactor mechanism for setting global compile options/program header

Replaced set_program_options/set_program_header functions with
push_compile_options/pop_compile_options and
push_program_header/pop_program_header.

Allows to roll-back to default or previously set options/header.
error is O(log(n)) now
support batched transformations