Updated random numbers

Previously there were 2 random number generator classes - Random and cachedRandom. These have been consolidated by:

• removing/deprecating the Random class
• renaming the cachedRandom class to Random

The Random class now stores its own buffer and uses the re-entrant system random functions so that each instantiation is not affected by each call to (re-)initialise the random number seed. The caching of the random numbers is not required since the generator can be reset using the same initial seed.