Adds Upstart version detection and separate conf, fixes sysv script, …

…compatible service stopping

edit version expected in test response

Bump version to 2.5.4

Bump version

Fix dashboard registration

bump version

Fix advanced url rewrites with session meta and path params

Fix 404 during reloads

Issue was happening on high load, because mainRouter object was
initialized with fresh router, before API routes was loaded into it.

Additionally added more mutexes.

Fix VirtualPath caching

Bug was introduced during refactoring, most likely as performance
optimization. `isVirtual` check never run if `CacheAllSafeRequests` was
true.

In addition test re-written to use full HTTP stack, and included case
when caching turned on.

Should fix TykTechnologies#1356

cache: EnabledForSpec should just use EnableCache

Don't require there to be a cached extended path too. Otherwise, one
can't use any sort of caching on an API without adding cached extended
paths.

At the same time, don't run the middleware if there are any cached
extended paths yet EnableCache is false. The docs tell the user to
enable the cache for the whole API, so that is expected.

Add a test to prove that caching of a simple API works. This test was
failing before, as the API does not have any cached extended paths.

Fixes TykTechnologies#1329.