Merge pull request etaler#129 from marty1885/apichange

more indexing method

Merge pull request etaler#121 from marty1885/master

Make tensor support iteration

Merge pull request etaler#113 from marty1885/master

Improve step support in indexing

Merge pull request etaler#108 from marty1885/master

Add more documentations

Merge pull request etaler#83 from marty1885/master

Fix! More fixes!!

add arrayfire interop