critical values for Johansen trace statistic
[jc]=c_sjt(n,p)
* n= number of zero eigenvalues under the null hypothesis
* p= order of time polynomial in the null-hypothesis
- p = -1, no deterministic part
- p = 0, for constant term
- p = 1, for constant plus time-trend
- p > 1 returns no critical values
* jc= a (3x1) vector of percentiles for the trace statistic for [90% 95% 99%]