JBIDE-16435 - NPE when starting/stopping LiveReload server when server with unknown type already exist
JBIDE-15966 - Livereload does not work with HTML files without <html>

Updated ScriptInjectionUtils

1. if there is node "head" - insert script at the end of the "head"
2. if there is no "head" and there is "body" - insert script at the end of the "body"
3. if there is no "head" and "body"and there is "html" - insert script at the end of the "html"
4. if there is no "head", "body" and "html" - insert script at the end of file
JBIDE-16439 - Upgrade Server tools dependency to 3.0.0
JBIDE-14999 - LiveReload: add option for refresh delay

Added a spinner in the Server Configuration Editor to set
the number of seconds that the livereload server should wait after
the application server published the resources that changed.

No need to restart the server to take the new delay into account (just
save the change).
The delay is seen as a job in the Progress View, so the user can cancel
the job is the delay was too long.

Added JUnit test.