Tawnycalc

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* Added THERMOCALC binaries for Windows, Apple & Linux.
Working but not tested extensively on Windows.
Working and tested on Linux.
Not as of yet tested on Apple.
* Minor fixes for some error checking.
* Tweaks for version numbering.
* Pip installable.

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* Update datasets.
* Added `icfile_denitions.txt`.
* Added `chemical_systems.py`.
* Add `Tute1_bulk-comp-stable-assemblage.ipynb` example and
associated data files.
* Add check for oxides.
* Minor documentation tweaks.
* Minor updates for THERMOCALC changes.

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* New data files added.
* New examples added.
* Thermocalc script files are now first class TawnyCalc
data objects.
* Load/Save/Copy functionality added to script and results objects.
* Improved handling of ThermoCalc subprocess. A default
timeout parameter has been added, along with better access
to resultant job standard output (via the `print_output()`
method).
* Updates for ThermoCalc 3.50

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* Initial release of `TawnyCalc`.
* Basic `ThermoCalc` job orchestration capabilities.