Fix cosmetic problems in YAML source

This change corrects problems reported by the `yamllint` linter.

Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.

test/samples/ignore_errors.yml

@@ -7,4 +7,3 @@
   - debug: msg="you should still see this"
   - fail:
   - debug: msg="you should NOT see this"
-  

test/samples/include.yml

@@ -3,4 +3,3 @@
   - included
 #- debug: msg="this is the second debug in the include"
 - debug: msg="this is the third debug in the include, and a is still {{a}}"
-

test/samples/l1_include.yml

@@ -1,3 +1,2 @@
 - debug: msg="this is the l1 include"
 - include: common_include.yml
-

test/samples/l2_include.yml

@@ -1,4 +1,3 @@
 - debug: msg="this is the l2 include"
 - debug: msg="a second task for l2"
 - include: common_include.yml
-

test/samples/localhost_include.yml

@@ -1,3 +1,2 @@
 - debug: msg="this is the localhost include"
 - include: common_include.yml
-

test/samples/lookup_template.yml

@@ -4,4 +4,3 @@
     my_var: "Bazinga!"
   tasks:
   - debug: msg="the rendered template is {{ lookup('template', 'template.j2') }}"
-

test/samples/test_include.yml

@@ -22,4 +22,3 @@
   #handlers:
   #- name: foo
   #  include: include.yml a="this is a handler"
-

test/samples/test_pb.yml

@@ -39,4 +39,3 @@
     debug: msg="this is the foo handler"
   - name: bar
     debug: msg="this is the bar handler, you should not see this"
-

test/samples/test_roles_complex.yml

@@ -3,4 +3,3 @@
   roles:
   - { role: role_a, tags: A, when: skip != "A" }
   - { role: role_b, tags: B, when: skip != "B" }
-

test/samples/with_together.yml

@@ -3,7 +3,7 @@
   gather_facts: no
   vars:
     alpha: [ 'a', 'b', 'c', 'd' ]
-    numbers:  [ 1, 2, 3, 4 ]
+    numbers: [ 1, 2, 3, 4 ]
   tasks:
   - debug: msg="{{ item.0 }} and {{ item.1 }}"
     with_together: