Apply JSON files for storing curation/annotation information

[haowang-bioinfo]

Description of the issue:

• This issue is derived from another ongoing issue (Migrating toward a binary-free repo #27), which aims to drive the repo toward binary-free mode eventually
• JSON is an open-standard and language-independent file format. It is human-readable text and commonly used for data interchange
• JSON files appear to be ideal for archiving information in GEM-type repo and helping the migration to binary-free mode, given that Matlab recently started to support JSON by providing built-in functions (jsondecode, jsonencode) for import/export.

Expected feature/value/output:

• It is attempted here to utilize JSON files for storing the model annotation information and curation results that are often cell array type variables in humanGEM and previously saved as .mat files
• Develop necessary tailored functions (e.g. prettyJson) to support the smooth application of JSON files
• Utilization examples are given below, and will be updated if modified

I hereby confirm that I have:

• Checked that a similar issue does not exist already

[haowang-bioinfo]

The .mat files under RxnAssociation subfolder have been processed according to above guidelines in PR #79. Next step probably is moving forward to MetAssociation subfolder.

[haowang-bioinfo]

Examples for loading/exporting cell array structure from/to a JSON file:

• Load JSON file abc.json to a variable:

variableName = jsondecode(fileread('abc.JSON'));

• Export a variable to a abc.json file to :

jsonStr = jsonencode(variableName);
fid = fopen('abc.json', 'w');
fwrite(fid, prettyJson(jsonStr));
fclose(fid);