Added
* general class Data for input handling [141](https://github.com/RECETOX/MSMetaEnhancer/pull/141)
* DataFrame class to read and handle tabular metadata input [141](https://github.com/RECETOX/MSMetaEnhancer/pull/141)
* implementation of blocking time in PubChem [145](https://github.com/RECETOX/MSMetaEnhancer/pull/145)
Changed
* Spectra class is an instantiation of Data class [141](https://github.com/RECETOX/MSMetaEnhancer/pull/141)
* fix throttling freezing the app [144](https://github.com/RECETOX/MSMetaEnhancer/pull/144)
Removed
* retired NLM (ChemIDplus) service [140](https://github.com/RECETOX/MSMetaEnhancer/pull/140)