Changed lambda_j to xi in test code. Updated test results. Added assertthat and tensorA to imports. Reduced no. iterations mcmc example.

Made new function to check alpha value passed to credible intervals. Added documentation for sliceTensor

Updated R version as tensorSlice funtion did not work correctly in earlier versions. Changes to tensorSlice made in previous commit undone as R update corrects the problem.

Merge branch 'master' of fhm-chicas-code.lancs.ac.uk:millerp/sourceR

# Conflicts:
#	R/data.R

Removed constraint that \sum_{j} x_{ijt} > 0.  This is not required as r_{ijt} is guaranteed to be positive by prior.

> model = HaldDP(...)