Use `make -j` to speed up build.
Switch to the new organization URLs.

Also, use https for GitHub links.
Merge pull request #413 from XhmikosR/org

Switch to the new organization URLs.
Merge pull request #414 from XhmikosR/make-j

Use `make -j` to speed up Travis CI build.
Merge pull request #412 from XhmikosR/master

Fix a few Cppcheck issues