Update plots to APL1P, use .pdf format rather than .png

Also add fig2pdf.m, to make conversion between the fig and the pdf
automatic.  This will also take care of font sizing.

	new file:   burg.pdf
	deleted:    burg.png
	new file:   burg_zero.pdf
	deleted:    burg_zero.png
	new file:   images/fig2pdf.m
	deleted:    gammaprime_diff_samples_dim_10.png
	new file:   kl.pdf
	deleted:    kl.png
	modified:   mchi2.fig
	new file:   mchi2.pdf
	deleted:    mchi2.png
	new file:   prob_dec_cost_v_gammaprime_no_context.pdf
	deleted:    prob_dec_cost_v_gammaprime_no_context.png
	new file:   prob_dec_cost_v_gammaprime_no_context_multiple.pdf
	deleted:    prob_dec_cost_v_gammaprime_no_context_multiple.png
	new file:   prob_dec_cost_v_nl_n_20.pdf
	deleted:    prob_dec_cost_v_nl_n_20.png
	new file:   water_prob_decrease.pdf
	deleted:    water_prob_decrease.png
	new file:   worst_case_probability.pdf
	deleted:    worst_case_probability.png
Update numerical section to reflect APL1P plots