add effects and ANOVA test

the effects function extracts the effects from an LmMod either produced with a formula and dataframe or from LmMod produced using a y and X matrix.  ANOVA test allows you to specify terms in an LmMod model to do an anova (full vs reduced) test.  You can specify 1 or more terms if the model was produced with a formula and data frame.  If the LmMod was produced with a y and X, you can specify the columns of X that you would like to group together.  ANOVAtest is a type to hold DF,SS,MS,F, and either the pval or -log10pval.  It has a show function that produces a table.  Below are some examples.

a=randn(100,4);
b=convert(DataFrame,a);

c=fit(LmMod,x1~x2+x3+x4,b)   #fit model with formula and dataframe
d=ANOVAtest(c,[2,3],log10pval=true)  #test of multiple columns of X with LmMod made with formula and dataframe
e=ANOVAtest(c,3)     #test of a single column of X with LmMod made with formula and dataframe
f=ANOVAtest(c,[3])    #shows that you can also do one term with a single cell array

g=fit(LmMod,c.model.pp.X,c.model.rr.y)   #fit model with X and y without formula or dataframe
h=ANOVAtest(g,[3,4])  #test of multiple columns of X with LmMod made without formula and dataframe
i=ANOVAtest(g,4)   #test of a single column of X with LmMod made without formula and dataframe
j=ANOVAtest(g,[4])    #shows that you can also do one term was a single cell array