Manually include all sub-modules and top-level types

This is needed so that `spectator/should` is not included by default.

src/spectator.cr

@@ -1,4 +1,4 @@
-require "./spectator/*"
+require "./spectator/includes"
 
 # Module that contains all functionality related to Spectator.
 module Spectator

src/spectator/includes.cr

@@ -0,0 +1,30 @@
+# This file includes all source files *except* `should.cr`.
+# The `should.cr` file contains the optional feature for using `#should` on all objects.
+# Since this is disabled by default, we don't include all files.
+# Including all files with a wildcard would accidentally enable `#should` by including it's file.
+# Unfortunately, that leads to the existence of this file to include everything but that file.
+
+# First the sub-modules.
+require "./internals"
+require "./dsl"
+require "./matchers"
+require "./formatters"
+
+# Then all of the top-level types.
+require "./example"
+require "./runnable_example"
+require "./pending_example"
+
+require "./example_hooks"
+require "./example_group"
+
+require "./expectation"
+require "./expectation_failed"
+require "./test_results"
+require "./runner"
+
+require "./result"
+require "./successful_result"
+require "./pending_result"
+require "./failed_result"
+require "./errored_result"