* rename singleshot to pershot

* update exp json data structures

* Add vector and matrix types for additional data

Add sys to imports in exception block

* add lineaer algebra functions for STL, matrix, json types

These allow linear operations add, sub, mul, div, square on
matrx, json and STL vector, array, map, unordered_map

move almost_equal to linalg

* remove unused Qobj members

* add non-qobj execute function

* Switch cvxopt usage to cvxpy

* Avoid numpy from conda on windows 3.5

The last numpy version with 3.5 support is below the minimum version of
numpy that cvxpy requires. This leads to a situation where we try
updating the conda install numpy with pip, and that causes things to
break. This isn't an issue on python >=3.6 because the conda packages
for numpy are kept up to date.

* Openblas is in conda-forge

* Add new average data class
* Add new average snapshot data container
* Add new snapshot classes to ExperimentData

* Add missing basis gates