GitLab

fix getInitialConcentrations

version bump to 0.5.2

fun accessors for initial amounts and concentrations

...to make the work with custom datatypes easier.

symbolics compat 

Strip whitespaces when reporting error messages from `readSBML`

Fix minimum compatible version of Julia and run CI on 1.5 and 1

Move test files to `test/data` to keep `test` clean

Also:

* replace `@warn` with `@error`
* actually test the logging message in `readSBML`, instead of showing an extra
  message saying to ignore it.

Make `sbml` a proper function, instead of a non-const anononymous one

Make `convert_simplify_math` constant

Make `default_symbolics_mapping` constant

Run CI with GitHub Actions on pull requests

Gitignore files downloaded during the tests

[skip ci]

Remove `DocumenterTools` from `docs/` environment

The package doesn't seem to be actually used, as far as I could see.

Update Project.toml

Support MathTime conversion to Symbolics, document the whole thing

Minor cleaning&merge of #65

(also ensures compatibility with the macro)