Documentation update for overloaded operators and packed_store_active2()
Vim syntax support for operators
Fixing some typos in docs and adding operators to language description
Adding release notes for 1.6.0
changes in examples (windows)
News update for 1.6.0
Bumping up ispc version to 1.6.0
Merge pull request #692 from ifilippov/embree

Changes in examples to make it work on Windows with VS2012 and some fixes for VS2010.
Merge pull request #691 from dbabokin/docs

Documentation update for overloaded operators and packed_store_active2()
Merge pull request #693 from dbabokin/release_151

Release 1.6.0