Added some validations for observation fields.
Added some validations for observation fields.

pleary/inaturalist,calonso-conabio/inaturalist,pleary/inaturalist,alexshepard/inaturalist,inaturalist/inaturalist,loarie/inaturalist,lucas-ez/inaturalist,calonso-conabio/inaturalist,HotFusionMan/inaturalist,alexshepard/inaturalist,loarie/inaturalist,alexshepard/inaturalist,inaturalist/inaturalist,inaturalist/inaturalist,HotFusionMan/inaturalist,lucas-ez/inaturalist,pleary/inaturalist,loarie/inaturalist,lucas-ez/inaturalist,calonso-conabio/inaturalist,alexshepard/inaturalist,HotFusionMan/inaturalist,loarie/inaturalist,inaturalist/inaturalist,calonso-conabio/inaturalist,lucas-ez/inaturalist,HotFusionMan/inaturalist,lucas-ez/inaturalist,pleary/inaturalist,pleary/inaturalist,calonso-conabio/inaturalist,alexshepard/inaturalist,inaturalist/inaturalist,HotFusionMan/inaturalist,loarie/inaturalist