Improvements:
* floating point operations are approx 4x's faster
* Now write quiet NaN's
* all read/write on floating point now done in C, so no more need for
lib/buffer_ieee754.js
* float values have more accurate min/max value checks
* add additional benchmarks for buffers read/write
* created benchmark/_bench_timer.js which is a simple library that
can be included into any benchmark and provides an intelligent tracker
for sync and async tests
* add benchmarks for DataView set methods
* add checks and tests to make sure offset is greater than 0
