Implementation of 307096 template and more changes

[RoryPTB]

The following changes have been made:

• Implementation of the 307096 template in replacement of 307080.
• Encoding of the barometer height obtained from the station list file.
• Support for nil reports.
• Support for transformation of multiple GTS messages in one file by partitioning according to the end of message signal nnnn.
• A CSV file is output during transformation, containing the decoded data of the input file where each row corresponds to each successfully converted report.
• Restructuring of the example data, addition of Cuban GTS data and synthetic data (which contains almost all possible groups that can be written in a synop report).
• Updated unit tests.
• Various bug fixes found by testing with different GTS data.

[david-i-berry]

Can you revert this to dev before we merge. We'll update the version number in a stand alone release.