github help links https -> http to fix build
Merge pull request #458 from hflynn/githelp

Github help links
testing.txt: Clarify text meaning.
Merge pull request #454 from mtbc/tests-title

Expand the title of the "writing tests" page
merge dev_4_4 -D org -I include -E exclude: PR 261 (Generate PDF using XeLaTeX)
merge dev_4_4 -D org -I include -E exclude: PR 368 (Cpp: Correct content and markup)
merge dev_4_4 -D org -I include -E exclude: PR 455 (Clean up testing.txt)