fixed the bug when end time was not updated after editing experiment
allowed single numbers in group ranges
changed time margin for new versions to 15 min
server time must be lesser than end time
added flags in experiment versions and implemented enabling and disabling of GA/DW tracking
small i18n tweak
hid Now button in datetime picked in A/B editor
added extra information about valid range when editing group ranges
adjusted how the warnings behave
removed console.log