move tests to subdirectory tests
do not import Testing in Main.hs
add testsuite to cabal file

Use "cabal test" to run tests. This should run all available test.
use ExitCodes to report status of tests
fix style in Main.hs
remove redundant do
Merge branch 'cabal_testsuite'

Conflicts:
	program/Main.hs
remove bomb from test/Main.hs