"mobi" data comes from semPLS

[NicholasDanks]

We have to require semPLS or explicitly reference mobi dataset from semPLS

[soumyaray]

just issued a PR for this! please check, accept it if it fixes the issue :)

[NicholasDanks]

Just want to check if there are other spots where it needs to be referenced. Can we not bundle mobi in the package?

[soumyaray]

let me check for other references. i'd rather not bundle it because end users will largely not need it or use it (except first time perhaps to run the demo code). no need to hog up their resources with it? also, its one less dependence for our package to rely on i feel.