Handle some possibly missing elements in NtS response The NtS XSD does not guarantee that value, value_min and value_max are present in a response. This led to circumventing the NOT NULL constraint for the waterlevel value by silently persisting missing values as zero and filling up missing confidence interval values especially for measurements with zeros.

#-*-makefile-*-
# Authors: Sascha Wilde <wilde@intevation.de>

.PHONY: all dependencies clean

all:	dependencies
	yarn build

dependencies:
	yarn install --check-files

clean:
	rm -rf ../web