Some benchmarks may run a few milliseconds which makes it kind of hard to visually compare, since the currently only available nanoseconds numbers can get very large in this case. Therefore this commit adds an optional command line flag --benchmark_time_unit which lets the user choose between ns and ms time units for displaying the mean execution time.

Fix missing include in map_test.cc

building with libc++.

Pass const State to Fixture::TearDown. Fix memory leak in fixture_test

Format json in README.md

Pass const state to Fixture::SetUp. Add map_test.

Add number of threads to State.

Having access to the thread count from within a benchmark is useful,
for when one wants to distribute a workload dynamically among the
benchmarks running in parallel e.g when using ThreadRange() or
ThreadPerCpu().

Add section on optimisations to README

Add aarch64 support to src/cycleclock.h.

Fix ARM /proc/cpuinfo parsing.

Support MSVC on appveyor

Also fix related warning message typos.

From google3's base/cycleclock.

Update README to mention UseRealTime for wallclock time measurements.

Also adding a use case in the API header.

Fixes #170

Fixes #165: CustomArguments ret type in README

* adds myself to AUTHORS/CONTRIBUTORS

Fixes #159: Add inclusion of cstdio to files using stdout, printf and etc.

add static_cast to get rid of warnings for intel compiler on linux platform

Fix get_git_version to use GIT_EXECUTABLE.

get_git_version CMake function uses 'git' command directly, instead of
GIT_EXECUTABLE variable. This causes CMake errors while generating
project files in environments, where 'git' command is not present
in PATH.

Fixes #144  CMake fails without Git