Add some tests for modules

* .gitignore now ignores *.got for *anything* under the tests/ directory
* runtests.sh ignores files in the tests/ directory that have the string
  "test_import_" in them, so they are not run as tests themselves
* Add a couple of basic module functionality tests

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

runtests.sh

@@ -17,7 +17,7 @@ echo "building"
 cargo build $flags || die "build failed"
 
 echo "testing"
-find "$tests" -type f -name '*.npp' | while read f; do
+find "$tests" -type f -name '*.npp' -not -name "*test_import_*" | while read f; do
     result="$(cargo run $flags -- "$f")"
 
     echo "$result" > "$f.got"