ICAw_set and ICAw_get

:construction: Work in progress, do not merge.
`ICAw_get` and `ICAw_set` are added in this branch - high level functions for safe eegDb database modifications.
ICAw_set will (in future) produce warnings when for example it is asked to change filtering of a file that is saved with altered filtering.
Another example: changing epoching for a file with marks and rejections - what should be done in this case. `ICAw_set` by default will not override current database settings in case of a conflict, but create a new version of given record.