SVGHMI: finally found why HMI:Input wasnt't initializing properly: vsprintf takes a list. Also, removed intermediate variable last_val, since edit_value() works on strings anyhow, and in case of formated floats, it is better to workl on already formated value.

SVGHMI: update generated XSLT

Allow printf-like formating in HMI:Input, usefull for example when dealing with floating point numbers.

SVGHMI: Switch from {object} to Map for "updates" global, for performance but also preventing wierd behaviour when iterating