Merge of updates from damian
Update of studentGrowthPercentiles
Got rid of extraneous text
get rid of conflicts
simex update based on AVI's suggestions
simex update delete setnames from extrap
simex update delete Corrected_Percentiles
reorganize quantile.data.simex and SGPercentiles
Merge pull request #349 from shangyi/master

Integration of .simex.sgp into studentGrowthPercentiles