Parse common attributes from notes

[htpusa]

Some older models hide reaction attributes such as GPRs in notes, these are currently not parsed. Notable example:

https://systemsbiology.ucsd.edu/sites/systemsbiology.ucsd.edu/files/Attachments/Images/InSilicoOrganisms/Ecoli/Ecoli_SBML/Ec_core_flux1.xml

The most important one is probably the GPR since it has an accessor and thus users are expecting to find it.

[htpusa]

"SUBSYSTEM" is another potentially relevant one.

[exaexa]

We're not going to put this into the parsing process directly (storing stuff in notes just....you shouldn't) but we can make a tiny wrapper atop SBMLModel that re-parses the notes in the right way without breaking anything else. I'll ping you with a test implementation asap.

[exaexa]

@htpusa in one other project we found that there's a unitilty to convert these annotations to the "proper" FBC form; you can do it with reframed:

model=reframed.load_cbmodel('something.xml',flavor='cobra')
reframed.save_cbmodel(model,'something_fbc.xml',flavor='bigg')

(Thanks go to Arianna Basile for this)

Also we should move this issue to the SBMLFBCModels. :)