added munsell color codes and USDA.TT.im.rda prior probs

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@127 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
added documentation USDA.TT.im.html

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@128 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fixed bug in the TT2tri.R with data()

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@129 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fixed class SoilGrids.Rd

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@130 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
updated index.php

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@131 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
added extract function for a list of rasters

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@132 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
added export of extract method to NAMESPACE

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gsif@133 edb9625f-4e0d-4859-8d74-9fd3b1da38cb