tc_efunc: evolving response and correlation function
In cszang/treeclim: Numerical Calibration of Proxy-Climate Relationships

see doc for dcc for details.

1	tc_efunc(chrono, climate, boot, sb, start_last, win_size, ci, method)

`chrono`	tree-ring chronology
`climate`	data.frame with climate parameters
`boot`	which bootstrapping method should be used? (or "none")
`sb`	logical: draw statusbar or not?
`start_last`	logical: start with last (oldest) window?
`win_size`	numeric: size of the first window in years
`ci`	numeric: p-level for confidence interval (must be in c(0.1, 0.05, 0.01)
`method`	character: method to be used (one of "response" or "correlation")
`p`	probability for rgeom, that determines distribution of sampling blocks for stationary bootstrap scheme