Merge pull request #2 from gboya/master

Use max-width and a viewport instead of max-device-width
add step for input number
Merge remote-tracking branch 'origin/master'
Revert "Use max-width and a viewport instead of max-device-width"

This reverts commit 7ae53e8232763b2628de0819ae3a74e21a3234fe.
Because of the problem with Samsung devices, remove input with type number for values expecting decimals, replace it by old text entry
change the approach regarding smart phone, do not support portrait mode. Add a tip message for turning device
review error message in case of portrait display
small changes on css, make controls bigger