Revert "use naturals with variable width as symbols"

This reverts commit 790dcf2c372a91d2780a20551c6e76c60ee934f6.
add self contained n-queens example
add standalone LPO example
fix warnings in ghc-7.8
Merge branch 'master' into usable-rules

Conflicts:
	tc/CO4/Test/TermComp2014/Util.hs