* Integrated the new dynamic kernel generator
* Added the corresponding tests, benchmarks and autotuning procedures
Adding .gitignore

Ignores contents of build directory and vim swap files.
Cleans git status messages.
Fixed issues with += and -= for element_prod() and element_div() (Issue 21)

+= and -= introduce temporaries, which needs improvements.
This, however, will be part of a larger refactoring (generator, further element-operations).
Merge branch 'master' of https://github.com/viennacl/viennacl-dev