init cmrse
CMRSE + cost select

. cost/files_select: multiple sort for 'data'
. cmrse per station and per network
match_orig, aggregate network

. function match_orig moved to this module
. agg_network: set a list of lists containing all the stations from one
network in each item
update to pandas 0.13 (sort in place)

new pandas do not allow inplace sorting of a series view; replaced sort
with order
exclude decades with missing data, global crmse, improv

. global_crmse: average crmse of one benchmark submission
. do_years: search years with missing data in every station in the same
network, then return all the years with no missing data
. improvement: average homogenized crmse / average inhomogenous crmse