IDL Wrapper for CAMB.

Need to set environment variable CAMB_DIR to the location of your CAMB 
executable if you are going to call CAMB (see below)

Without /runcamb set, will just make a parameter file for you.  With it set, 
will call CAMB, and read in/parse the CAMB output files, returning results
as a structure with several tags depending on you CAMB settings.

One of my motivations was to quickly make param files with many redshifts
for the transfer function/power spectrum.  You can pass transfer_redshift
an array of redshifts (make sure they are from high to low!), along with
arrays of output file names for transfer_filename and transfer_matterpower 
(these are all easy to generate in an automated way on your own), and it 
will format the param file and parse the output file for you.

Currently, vector modes are not well tested!


The function sig8_to_scalamp.pro will take a value of sigma_8, and return
the appropriate value of the scalar amplitude to pass to CAMB to get
that sigma_8 at z=0.