Added:
Added:

Support functions:
1. rev_col_subset. Allows for the matrix to be subset by columns from high indices to low indices (reverse of normal subsets)
2. rev_row_subset. Allows for the matrix to be subset by rows from high indices to low indices (reverse of normal subsets).
3. expand_grid_red() modified version of expand.grid for two variables.
4. Modified pseudo_ functions to make all functions positive. So, these are the actual values.

Ported functions from R into RcppArmadillo:
1. ARMAtoMA_arma
2. ARMAacf_arma
3. cfilter - convolution filter
4. rfilter - recursive filter

New functions:
1. arma_to_wv - arma process conversion to wavelet variance.
2. objFun_find_biwc - objective function to find the tuning constant
3. find_biw - function that finds tuning constant
4. objFun_sig_rob_bw - function that finds the robust WV.
5. sig_rob_bw - function that computes the robust estimator.

SMAC-Group/gmwm,SMAC-Group/gmwm,SMAC-Group/gmwm,SMAC-Group/gmwm