StepCLE : <anonymous>: no visible global function definition for
  ‘rnorm’
StepFRM : <anonymous>: no visible global function definition for ‘rexp’
StepGillespie : <anonymous>: no visible global function definition for
  ‘rexp’
StepPTS : <anonymous>: no visible global function definition for
  ‘rpois’
StepSDE : <anonymous>: no visible global function definition for
  ‘rnorm’
as.timedData: no visible global function definition for ‘time’
discretise: no visible global function definition for ‘ts’
gillespie: no visible global function definition for ‘rexp’
gillespied: no visible global function definition for ‘rexp’
gillespied: no visible global function definition for ‘ts’
imdeath: no visible global function definition for ‘rexp’
imdeath: no visible global function definition for ‘runif’
imdeath: no visible global function definition for ‘stepfun’
mcmcSummary: no visible binding for global variable ‘sd’
mcmcSummary: no visible global function definition for ‘par’
mcmcSummary: no visible global function definition for ‘ts’
mcmcSummary: no visible global function definition for ‘acf’
mcmcSummary: no visible global function definition for ‘hist’
metrop: no visible global function definition for ‘runif’
metrop: no visible global function definition for ‘dnorm’
normgibbs: no visible global function definition for ‘rnorm’
normgibbs: no visible global function definition for ‘rgamma’
rcfmc: no visible global function definition for ‘rexp’
rcfmc: no visible global function definition for ‘stepfun’
rdiff: no visible global function definition for ‘rnorm’
rdiff: no visible global function definition for ‘ts’
rfmc: no visible global function definition for ‘ts’
simTs: no visible global function definition for ‘ts’
simpleEuler: no visible global function definition for ‘ts’
Undefined global functions or variables:
  acf dnorm hist par rexp rgamma rnorm rpois runif sd stepfun time ts
Consider adding
  importFrom("graphics", "hist", "par")
  importFrom("stats", "acf", "dnorm", "rexp", "rgamma", "rnorm", "rpois",
             "runif", "sd", "stepfun", "time", "ts")
to your NAMESPACE file.