add docu for User::getAllEmails() and EMail
fix ContentType header for HTTP GET requests

it should not get set
removing support for vnd.github.v3 for calls to /user/emails

somehow it does not work with this code. with plain curl it does. weird.
update user test docu
add Uncrustify config (still not 100% as desired)

probably bug in Uncrustify: pointer operator ('*') in preprocessor
macros are interpreted as arithmetic operators :-/
converted tabs to 4 spaces in public headers
converted tabs to 4 spaces in private headers
converted tabs to 4 spaces in sources
applied Uncrustify to public headers
applied Uncrustify to private headers
applied Uncrustify to sources
converted tabs to 4 spaces in tests
applied Uncrustify to tests