Revise the boolean setting controlling external configuration hot-reloading

The addition of the setting within the external application.conf file to control
enabling/disabling runtime hot-reloading for #235 was hastily done.

In retrospect, it would be better to control this behavior by use of a System
property which complements the system property already used to specify the
external configuration location.

    java -Dninja.external.reload=true -Dninja.external.configuration=app.conf
Merge pull request #238 from gitblit/hotreload2

Revise the boolean setting controlling external configuration hot-reloading
Added test for NinjaCache.
Merge branch 'develop' of github.com:ninjaframework/ninja into develop
Merge branch 'develop' into bazi-multiple-regex-route

Conflicts:
	ninja-core/src/site/markdown/developer/changelog.md
Merge branch 'bazi-multiple-regex-route' into develop
Removed localized lookup in Freemarker templates. Not needed as Ninja does i18n already
update routing docs to reflect changes in PR #236

routes can have multiple regex parts
modify routing docs