Win: Make HTML_RESULT event match other platforms and disable dev tools when not DEBUG. When javascript_run() does not have a result other platforms return a NULL pointer, but Edge Chromium returns a string "null"; this change checks for "null" and makes it a NULL pointer instead. This may cause problems when a "null" string result is the expected result. Additionally disable developer tools for the HTML widget when DEBUG is not defined when compiling.

# Set these here to change the version for all platforms
DW_MAJOR_VERSION=3
DW_MINOR_VERSION=0