added fixedMargin argument for conting. tables

fixedMargin determines which margin is fixed for the independent
multinomial sampling plan.
add fixedMargin to post. samp. of cont. tables
started null gibbs sampler for pois cont. tab.
Added sampling for cont. tab. except hypergeom
recompiled documentation
fixed noSample argument for cont. tab.
sampling for hypergeom null cont. tab. added
Added skel. of hypergeom alt. sampler (no guts)
fixed recompute() with cont. tables
added fixedMargin argument for conting. tables

fixedMargin determines which margin is fixed for the independent
multinomial sampling plan.
add fixedMargin to post. samp. of cont. tables
started null gibbs sampler for pois cont. tab.
Added sampling for cont. tab. except hypergeom
recompiled documentation
fixed noSample argument for cont. tab.
sampling for hypergeom null cont. tab. added
Added skel. of hypergeom alt. sampler (no guts)
fixed recompute() with cont. tables
Rebuild documentation
Merge pull request #27 from richarddmorey/posteriorContingency

Posterior contingency