cboettig/wrightscape: Wrightscape: MLE for multi-peak OU processes on phylogenies

A fast C code implementation of maximum likelihood calculations for a multi-peak OU process with independent alpha, sigma, and theta parameters for each peak on phylogenetic trees (an extension of the ouch model). Includes R package wrapper as interface to C code. Likelihood calculation presented in http://www.carlboettiger.info/files/phylo-covariance.pdf, later the basis for: Jeremy M. Beaulieu, Dwueng-Chwuan Jhwueng, Carl Boettiger and Brian O'Meara, (2012). Modeling Stabilizing Selection: Expanding the Ornstein-Uhlenbeck Model of Adaptive Evolution, Evolution 66 (8) 2369-2383. doi:10.1111/j.1558-5646.2012.01619.x