Cosimpy

- Modified a bug in importFields_cst method
- Solved a bug due to newer matplotlib version (>3.4)
- Now it is required a matplotlib version higher than 3.4

- The way the additional properties are managed in the EM_Field class has been substantially changed. From the user side, this will affect the following methods:
* `EM_Field.compPowDens`;
* `EM_Field.compDepPow`;
* `RF_Coil.powerBalance`;
* `RF_Coil.saveRFCoil`: The RF_Coil instance is saved with a new file version;
* `RF_Coil.loadRFCoil`: It is not be possible to load the RF_Coil instances saved with a previous version of CoSimPy.
- New methods are available:
* A `compQMatrix` method is available for the EM_Field class;
* A `__getitem__` method is available for the EM_Field class;
* A `addProperty` method is available for the EM_Field class;
* A `getProperty` method is available for the EM_Field class;
* A `maskEMField` method is available for the EM_Field class;
* A `plotEMField` method is available for the EM_Field class. This method replaces the old `plotB` and `plotE` methods which will be removed in the next vesions of CoSimPy.
* A `plotProperty` method is available for the EM_Field class.
- A `nPorts` property is added to the RF_Coil class;
- The `__getitem__` method of the S_Matrix class is improved;
- Personalised exceptions are implemented to provide the user with a clearer feedback in case of errors.

A bug in the "compSensitivities" method of the EM_Field class has been fixed

General repackaging of version 1.3.0.
The following minor improvements have been implemented:

RF_Coil

- Solved a bug in the saveRFCoil method when the RF coil is saved without description;
- Edited the status print of the saveRFCoil and loadRFCoil methods.

EM_Field

- Edited the status print of the importFields methods.

- A new \_\_sub__ method in the S_Matrix class allows to perform the cascade connection between the last port of a first S_Matrix instance and the first port of a second just as: S_res = S_1 - S_2;
- The importTouchstone method of the SMatrix class has been improved to fully support the v1.1. Touchstone® File Format Specification by IBIS. It will be possible to import also Z- and Y-parameters. Furthermore, providing to the method the relevant information through a dictionary, the same method will also be able to import a simple ascii file formatted by columns;
- An exportTouchstone method will be available in the S_Matrix class to export the S-, Z- or Y-parameters either according to the v1.1. Touchstone® File Format Specification by IBIS or to a columns formatted ascii file;
- Two new methods in the S_Matrix class (sMatrixOpen, sMatrixShort) will allow to generate an instance of a 1-port open or 1-port short over defined frequency values;
- The existing methods to generate T and PI circuits accept None arguments for longitudinal and transversal parameters respectively, to substitute them with short and open circuits respectively;
- The original S matrix, S0, is saved in way allowing for the external circuitry losses computation accounting for all the consecutive connections to the S0 matrix;
- A new method is available in the S_Matrix class (setAsOriginal) to set the S_Matrix instance resulting from the connections with external circutries as unconnected. In this way, during powerBalance, the connected circuitry losses will be assigned to the source “other”;
- A new method of the S_Matrix class (plotSPanel) allows to plot, in a single multipanel figure, the S parameters of a multiport device in dB;
- The importFields_cst method of the EM_Field class is improved to support the import of the electromagnetic field exported by CST as .h5 binary file;
- Two new methods of the RF_Coil class (saveRFCoil, loadRFCoil) allow to save and load the RF_Coil instance in proprietary binary files;
- New methods are available in the RF_Coil class (duplicatePortsParallel, duplicatePortsSeries) to duplicate existing ports of a simulated device;
- A new method is available in the RF_Coil class (connectPorts) to connect together two or more port pairs, through given circuitries, whose S matrices are properly given by the user.

- Added three hidden properties to S_Matrix class allowing to store incident powers and original S matrix prior to a connection
- Added a method for voltages and currents computation at the supply ports of the S Matrix before and after loading
- Added a method for power balance computation
- Added a method for power loss density computation
- Added a method for power deposition computation
- sMatrixTrLine allows for transmission lines with characteristic impedances different from the port impedances