Add GetKey to python2, closes Cryptolens#18

Remove dependency on pycryptodome (Cryptolens#17)

* Remove dependancy on PyCryptodome (Martin's code)

* Minor fix to signature verification

* Update setup.py

Fix machine code generation on Mac for Python 2 & 3

Update setup.py

Python2 fix in Cryptolens#11

Add deactivate

Create trial key (Cryptolens#10)

* Start on CreateTrialKey

* Update input parameters

* Update docs

* Update setup.py

Fix error handling and update version number

Update version to the tar file

Add GetMachineCode method (Cryptolens#5)

* Add GetMachineCode method

* Add IsOnRightMachine method

* Update package info

* Update docs