We use the SHGetValueA on Windows to retrieve the MHz of the processor
but this requires the shlwapi library. Previous to this patch the
library was linked with a MSVC specific pragma but there is no
guarantee that on Windows we will be using MSVC. Therefore, it is much
compile agnostic to use the standard CMAKE library linking mechanism
to provide the definition of SHGetValueA

Introduce CSV reporter

Change the available Benchmark options

Fix and improve BENCHMARK macros.

Fix #96: Prevent times from being negative.

The calculation was actually inside the loop for a reason.

This reverts commit 47442b90.

Add variadic macro for BENCHMARK_TEMPLATE in c++11 and beyond.