Modifications of mixed models

Thoses modifications  deal with patients discriminations
TcGSA formula updated
rproj misc
Attempt to merge
Formula and plot 1GS updated
Merge pull request #4 from damienchimits/master

TcGSA.formula OK still a few glitch in plot1GS with NAs...
plot1GS fixed: precluster option added
Merge pull request #6 from borishejblum/damienissues

v0.9.9: patient heterogenity is now implemented
Merge pull request #2 from borishejblum/master

plot1GS fixed
Function TcGSA.subset

Creation of a function for obtaining a subset of a TcGSA object
Modification of TcGSA.formula for the time function
Merge pull request #7 from damienchimits/master

Function TcGSA.subset + TcGSA formula for patient discrimination