publicize GetDllPath + option to use latest DLL + exec and eval accept utf8 code

[bentheiii]

3 changes:

• GetDllPath moved to public: useful for people who want to make sure they're using the right python environment
• Option to use latest DLL: needed for machines with both 2.7 and 3.x that want to use 3.x. changes the version search to be reversed (last version is tested first)
• utf8: The cleaned strings are now convererted to utf8, allowing for strings in other languges in 3.x

[pyscripter]

Have a look at PythonVersions.pas. It does all that and more.

[bentheiii]

Noted for the first two points, I don't think it can handle the the third (non-ascii source code).

If it doesn't I will close and re-open with only the utf-8 fix.

[pyscripter]

You can always encode the text your self before passing it to python. This is what PyScripter does. The thing is that Python 2.x expects ansi and Python 3.x expects utf8. Maybe I can add a function overload that expects utf8. But it would need to be checked for Delphi/FPC compatibility.

[pyscripter]

Superceded by #59

[idanmiara]

Please advise how to set python4delphi to choose the newest (and not oldest) available python dll (as currently if two versions are available at the same folder you choose the older one).
If it's not available, we can send you a pull request for this feature again.
Thanks!

[pyscripter]

Have a look at PythonVersions.

GetLatestRegisteredPythonVersion(PythonVersion);
PythonVersion.AssignTo(PythonEngine);

See also Demo34