create boilerplate for maintenances #4
add the possibility to listen to more stores #4
fill the planned maintenances with data #4
use the listen to stores appropriate mixins #4

- when one store is needed, use listenToStoreSimpleMixin
- if more are needed, use listenToStores
add more sample data - machines with maintenance #4
add no employee to the employee select #4
display the company name in the edit maintenance screen #4
delete unused month list code #4
prefill the employee into the employee select #4
fully link note & calendar to state #4
add key to every <MenuItem /> #4
correct the code to remove warnings #4
use the -1 instead of null as a key in arrays for react #4
hide the popover on click outside #4
remove commented code
display the machines on the maintenance edit page #4
mark the machines, that are planned for maintenance #4
fix the maintenance form, so it can be used for new maintenances #4