Type that player may never hold certain tiles.

The only complexity this adds is to the structure 
of a Tile.  Otherwise, it simplifies things.
document the storeable tile commit as interesting
added cabal file and placated 'check' and 'build'

Included indentation correction of if statements
in do blocks, as cabal doesn't use DoAndIfThenElse
by default.
Merge branch 'master' into type_storeables
display suns in sorted order
Merge branch 'master' into type_storeables
add a board layout for stored tiles (unused)
update readme