print out coefficients of X^-1 and X^-2 of alpha_n
list the period lengths in dependency of characteristic.
some more examples for experimentation
Merge branch 'master' of sl2z.de:olaf/continued-fractions

Resolved Conflicts:
	examples-sqrt.lisp
clean up and reorganise the code for general cf expansions of power series
remove examples using old code
add missing exports and move with-cf macro closer to class def
rewrite the specialisation of the cf algorithm for the square roots
move alternative implementation into a separate file
get rid of redundant example code