[SDS-284] barrier/wait command and multiple measurements

[QFer]

NOTICE: the examples in the repository are failing because they are run on production, which doesn't contain v2 api yet.

Not related to the changes for multi measurements (some boyscouting):

• All files containing the license is changed from http:// to https://
• Added p as an alias for u1 to qiskit backend (p and u1 are aliases)

Related to the changes for multi measurements:

• Added barrier (Qiskit/ProjectQ) and wait (Qiskit) command support where applicable (and when backend supports it through the allowed_operations)
• Implemented to use V2 of the API
• Reading the new flags for multi measurement (parallel computing/multi_measurement) coming from the backend. The flags can be used by the user to know if we have multiple measurements in the backend. Adjustments for multiple measurements in result structures:
• For Qiskit backend: The result structures return V1-results as usual (in case of multi measurement the last measurement block). The structure is extended with V2 results (the multiple measurement results).
• For ProjectQ backend: The V1 result structures return results as usual (in case of multi measurement the last measurement block refered to as V1_MEASUREMENT_BLOCK_INDEX).
• Changes in the docstrings explaining the changed structures.
• Unit tests added and changed

[coveralls]

Coverage remained the same at 100.0% when pulling d4d0daae655c1be31f878100d58158767cf10e13 on feature/SDS-284/barrier_command into e623e4f747846dddbcb7d2e057e80e66ebd2cdd1 on dev.