Missing hyphen in git-http-backend

Add missing hyphen in the command name.
One more...
Add missing hyphen

The command is git diff --check.
Merge pull request #140 from paveljanik/patch-3

Missing hyphen in git-http-backend
Merge pull request #141 from paveljanik/patch-4

Add missing hyphen
Fix git's output

When committing to a branch, git commit prints the branch name, "slow-blink" this time, not master.
Format git username uniformly.
Merge pull request #144 from paveljanik/patch-5

Fix git's output
Merge pull request #145 from paveljanik/formatgituser

Format git username uniformly.
Fix some typos

Signed-off-by: Thomas Ackermann <th.acker@arcor.de>
Fix commit reference
Merge pull request #146 from tritemio/master

Fix commit reference
Merge pull request #143 from tacker66/fix_some_typos

Fix some typos
Contributing.md
Translation and figure notes -> contributing.md
License for print edition
asciidoc != markdown